diff --git a/config/auth.php b/config/auth.php
index 5ff0f16..4a2cc27 100644
--- a/config/auth.php
+++ b/config/auth.php
@@ -1,24 +1,13 @@
 <?php
-// Auth guards — require functions.php (and session_start) before this file.
+// Auth guards — require functions.php (and the shared session, started by
+// platform_connect() in config/db.php) before this file.
 //
-// This install owns its passwords: they live in `users.password_hash` and
-// views/auth/login.php is a real form. There is no identity provider in front
-// of the app.
-
-function require_login(): array {
-    if (empty($_SESSION['user_id']) && ($GLOBALS['pdo'] ?? null) instanceof PDO) {
-        // «Manter sessão iniciada»: antes de mandar para o login, tenta repor
-        // a sessão a partir do cookie (config/functions_remember.php).
-        remember_resume($GLOBALS['pdo']);
-    }
-    if (empty($_SESSION['user_id'])) {
-        $return = $_SERVER['REQUEST_URI'] ?? '';
-        $qs     = $return ? ('?return_to=' . urlencode($return)) : '';
-        header('Location: ' . base_url('views/auth/login.php' . $qs));
-        exit;
-    }
-    return $_SESSION['user'];
-}
+// Auditoria 2026-09-24, ponto 1.3: estas funções deixaram de ter lógica
+// própria de sessão/roles — delegam em
+// shared/platform-tools/functions_auth.php (auth_check/auth_user/
+// auth_at_least/auth_is/...), ligado em config/db.php ('auth' => 'shared').
+// Os nomes e assinaturas mantêm-se exactamente iguais porque há ~30
+// ficheiros em views/ a chamá-las; só o que está por baixo mudou.
 
 // ─── Role ladder ─────────────────────────────────────────────────────────────
 //   sysadmin — super-admin (backups, platform update, app_base_url).
@@ -29,6 +18,12 @@ function require_login(): array {
 //   client   — portal-only.
 // is_admin()/require_admin() = sysadmin OR admin. is_staff()/require_staff()
 // also includes the plain `staff` role.
+//
+// A hierarquia é agora expressa por posto numérico (auth_roles_register() em
+// config/db.php: sysadmin=100, admin=80, staff=40, client=10) em vez dos
+// antigos in_array() — auth_at_least('admin') dá exactamente o mesmo
+// resultado que in_array($role, ['sysadmin','admin']) dava, porque staff(40)
+// e client(10) ficam sempre abaixo de admin(80).
 
 // Resolves the dashboard path for a given role. Used by index.php, the auth
 // pages, and require_admin()'s bounce fallback so all four agree on routing.
@@ -41,12 +36,27 @@ function post_login_destination(string $role): string {
     };
 }
 
+function require_login(): array {
+    // O «manter sessão iniciada» já corre em config/db.php
+    // (platform_connect(['remember' => true, ...]) chama auth_remember_resume()
+    // logo no arranque, antes de qualquer view), por isso não há aqui nada
+    // equivalente ao antigo remember_resume() manual — se havia um cookie
+    // válido, $_SESSION['user'] já está preenchido a esta altura.
+    if (!auth_check()) {
+        $return = $_SERVER['REQUEST_URI'] ?? '';
+        $qs     = $return ? ('?return_to=' . urlencode($return)) : '';
+        header('Location: ' . base_url('views/auth/login.php' . $qs));
+        exit;
+    }
+    return auth_user();
+}
+
 // Accepts sysadmin + admin only. Plain staff and clients are bounced to the
 // dashboard appropriate for their role (avoids redirect loops when an admin-
 // only page bounces a staff user).
 function require_admin(): array {
     $user = require_login();
-    if (!in_array($user['role'], ['sysadmin', 'admin'])) {
+    if (!auth_at_least('admin')) {
         header('Location: ' . base_url(post_login_destination($user['role'] ?? '')));
         exit;
     }
@@ -57,7 +67,7 @@ function require_admin(): array {
 // Clients are redirected to the public index.
 function require_staff(): array {
     $user = require_login();
-    if (!in_array($user['role'], ['sysadmin', 'admin', 'staff'])) {
+    if (!auth_at_least('staff')) {
         header('Location: ' . base_url('index.php'));
         exit;
     }
@@ -70,7 +80,7 @@ function require_staff(): array {
 // the role-appropriate sessions list.
 function require_session_ownership(array $session): array {
     $user = require_staff();
-    if (in_array($user['role'], ['sysadmin', 'admin'], true)) return $user;
+    if (auth_at_least('admin')) return $user;
     if ((int) ($session['photographer_id'] ?? 0) !== (int) $user['id']) {
         header('Location: ' . base_url('views/sessions/index.php'));
         exit;
@@ -82,7 +92,7 @@ function require_session_ownership(array $session): array {
 // Plain admins are sent back to their dashboard.
 function require_sysadmin(): array {
     $user = require_login();
-    if ($user['role'] !== 'sysadmin') {
+    if (!auth_is('sysadmin')) {
         header('Location: ' . base_url(post_login_destination($user['role'] ?? '')));
         exit;
     }
@@ -90,34 +100,34 @@ function require_sysadmin(): array {
 }
 
 function current_user(): ?array {
-    return $_SESSION['user'] ?? null;
+    return auth_user();
 }
 
 // True for sysadmin + admin (NOT plain staff).
 function is_admin(): bool {
-    return in_array(current_user()['role'] ?? '', ['sysadmin', 'admin']);
+    return auth_at_least('admin');
 }
 
 // True for any backoffice user (sysadmin + admin + staff). Use this to show
 // a UI element that any non-client backoffice user should see.
 function is_staff(): bool {
-    return in_array(current_user()['role'] ?? '', ['sysadmin', 'admin', 'staff']);
+    return auth_at_least('staff');
 }
 
 function is_sysadmin(): bool {
-    return (current_user()['role'] ?? '') === 'sysadmin';
+    return auth_is('sysadmin');
 }
 
 // True for plain admins (not sysadmin, not staff). Useful for "hide from
 // sysadmin" edge cases; most code wants is_admin() or is_sysadmin().
 function is_admin_role(): bool {
-    return (current_user()['role'] ?? '') === 'admin';
+    return auth_is('admin');
 }
 
 // True for plain staff only — the assignment-only role. Used to scope queries
 // to "photographer_id = me" instead of returning all sessions.
 function is_staff_role(): bool {
-    return (current_user()['role'] ?? '') === 'staff';
+    return auth_is('staff');
 }
 
 // Back-compat shim: every is_designer() caller now means "is plain admin".
@@ -125,21 +135,22 @@ function is_designer(): bool {
     return is_admin_role();
 }
 
+// Refreshes the session's user fields (name/email/role) without a full
+// login — used after a profile edit or an admin-driven role change, where a
+// full auth_login() (rehash checks, last_login stamp, audit "auth.login")
+// would be the wrong event to log. Still rotates the session id: any
+// privilege/credential change should get a fresh one.
 function auth_set_session(array $user): void {
-    // Rotate the session id on every privilege change (login, registration,
-    // password reset). Defeats session fixation: an attacker who pre-seeded
-    // FIT_SESS now ends up holding a dead id while the real user gets a fresh
-    // one. The CSRF token is rotated alongside the session id.
+    auth_session_regenerate();
     if (session_status() === PHP_SESSION_ACTIVE) {
-        session_regenerate_id(true);
         unset($_SESSION['csrf_token']);
     }
-    $_SESSION['user_id'] = $user['id'];
+    $_SESSION['user_id'] = (int) $user['id'];
     $_SESSION['user']    = [
-        'id'          => $user['id'],
-        'name'        => $user['name'],
-        'email'       => $user['email'],
-        'role'        => $user['role'],
+        'id'    => (int) $user['id'],
+        'name'  => $user['name'],
+        'email' => $user['email'],
+        'role'  => $user['role'],
     ];
 }
 
diff --git a/config/db.php b/config/db.php
index 7776411..28fed34 100644
--- a/config/db.php
+++ b/config/db.php
@@ -66,36 +66,57 @@ try {
     _bootstrap_fail('PDO connect failed: ' . $e->getMessage());
 }
 
-// Distinct session cookie per app so installs that share a host (e.g.
-// development.andmore.pt/id.andmore.pt/ and /fitme3070.pt/) don't overwrite
-// each other's PHPSESSID. Must run before session_start().
-//
-// Cookie e modo estrito definidos aqui, no código, para valerem em qualquer
-// servidor: antes o cookie saía só com path=/ (sem Secure, HttpOnly nem
-// SameSite) e o PHP aceitava IDs de sessão inventados pelo cliente.
-if (session_status() === PHP_SESSION_NONE) {
-    ini_set('session.use_strict_mode', '1');
-    ini_set('session.use_only_cookies', '1');
-    ini_set('session.cookie_httponly', '1');
-    ini_set('session.cookie_samesite', 'Lax');
-    if (request_is_https()) ini_set('session.cookie_secure', '1');
-    session_name('FIT_SESS');
-    session_start();
-}
-
 // ─── Ligação ao platform-tools ───────────────────────────────────────────────
 //
-// A app mantém as suas próprias passwords e sessão (`config/auth.php`,
-// `views/auth/login.php`) — não passa a usar o functions_auth.php partilhado
-// (`'auth' => 'own'`), porque a `auth_attempts` desta app não tem a coluna
-// `identifier` que o throttle partilhado exige (tem `ip`+`scope`, do seu
-// próprio throttle em functions_throttle.php). Ainda assim liga-se ao
-// bloqueio de IP da frota, ao router das páginas de sistema (Backups,
-// Actualizações, Auditoria, IP bans, Geo, Origem das visitas, Hub) e ao
-// resto do platform-tools, tudo por cima da autenticação própria.
+// Auditoria 2026-09-24, ponto 1.3: a app passou a usar a autenticação
+// partilhada (`shared/platform-tools/functions_auth.php`) em vez da sua
+// própria — login, sessão, roles e guardas (config/auth.php,
+// config/functions_user.php) agora chamam auth_attempt()/auth_login()/
+// auth_at_least()/etc. por baixo, com os mesmos nomes de função de sempre
+// para os ~30 ficheiros que os chamam não mudarem.
+//
+// O cookie de sessão (nome, Secure/HttpOnly/SameSite, modo estrito) passa a
+// ser inteiramente gerido por auth_session_start() através da opção
+// 'session' abaixo — o bloco que estava aqui antes (ini_set + session_start
+// manuais) foi removido para não haver dois sítios a configurar a mesma
+// sessão.
+//
+// `users` já tem exactamente as colunas por omissão do auth_schema()
+// (id, email, name, password_hash, role, is_active, last_login_at,
+// last_login_ip — confirmado via information_schema em produção), por isso
+// não é preciso mapear nada em 'schema'.
+//
+// auth_attempts (o throttle da APP, config/functions_throttle.php — ip+scope,
+// cobre login/registo/recuperação) continua a ser o único throttle de login
+// usado; o throttle do módulo partilhado (auth_throttle_check/hit, que exige
+// `identifier`) não é chamado, para não duplicar a defesa do mesmo
+// formulário com duas contagens diferentes. A tabela foi tornada conforme na
+// mesma (database/migration_20260925_shared_auth_attempts.sql) para o
+// relatório de saúde abaixo ('conformance' => 'report') não acusar erro e
+// para deixar a porta aberta a usar o throttle partilhado no futuro. Ver
+// views/auth/login.php para a nota completa.
 require_once dirname(__DIR__) . '/shared/platform-tools/functions_connector.php';
 platform_connect($pdo, [
-    'auth'        => 'own',
+    'auth'    => 'shared',
+    'roles'   => [
+        // Preserva a hierarquia que config/auth.php já tinha (sysadmin >
+        // admin > staff > client, por in_array(), não por posto numérico):
+        // staff acima de client, e os dois abaixo de admin(80), para
+        // require_staff()/is_staff() continuarem a excluir clientes e
+        // require_admin()/is_admin() continuarem a excluir staff e clientes.
+        // sysadmin(100)/admin(80)/user(10) já vêm registados por omissão.
+        'staff'  => 40,
+        'client' => 10,
+    ],
+    'session' => [
+        'name'     => 'FIT_SESS',
+        'samesite' => 'Lax',
+        // secure/httponly ficam a cargo de auth_session_start(): secure
+        // segue o mesmo critério de HTTPS que o bloco antigo usava,
+        // httponly está sempre ligado.
+    ],
+    'remember' => true,   // «Manter sessão iniciada» — agora auth_remember_*
+                           // do platform-tools; ver views/auth/login.php.
     'guard'       => 'require_sysadmin',
     'router'      => true,
     'conformance' => 'report',   // nunca recusa — só reporta no health endpoint
diff --git a/config/functions.php b/config/functions.php
index 699c3ca..1ad6cc0 100644
--- a/config/functions.php
+++ b/config/functions.php
@@ -15,9 +15,11 @@ require_once __DIR__ . '/functions_secrets.php';   // setting_or_env()/setting_s
 require_once __DIR__ . '/functions_db.php';        // generic DB helpers
 require_once __DIR__ . '/functions_audit.php';     // registo de auditoria (platform-tools) + audit()
 require_once __DIR__ . '/functions_trash.php';     // lixeira: soft delete + eliminação só após 30 dias
-require_once __DIR__ . '/functions_user.php';      // auth_login/register, password reset, user creators
+require_once __DIR__ . '/functions_user.php';      // register/reset/user creators (auth itself: platform-tools)
 require_once __DIR__ . '/auth.php';                // require_login/admin/staff/sysadmin(), role helpers
-require_once __DIR__ . '/functions_remember.php';  // «Manter sessão iniciada»
+// «Manter sessão iniciada»: shared/platform-tools/functions_remember.php,
+// ligado por platform_connect(['remember' => true]) em config/db.php — já não
+// há um functions_remember.php local (auditoria 1.3).
 require_once __DIR__ . '/functions_throttle.php';  // per-IP attempt throttle for the auth endpoints
 require_once __DIR__ . '/functions_migrations.php';// platform_update.php migrations runner
 
diff --git a/config/functions_remember.php b/config/functions_remember.php
deleted file mode 100644
index 5520633..0000000
--- a/config/functions_remember.php
+++ /dev/null
@@ -1,140 +0,0 @@
-<?php
-// ─── «Manter sessão iniciada» ────────────────────────────────────────────────
-// Mesmo desenho do platform-tools functions_remember.php, reimplementado aqui
-// porque esta app tem autenticação própria (config/auth.php, não
-// functions_auth.php partilhado) e chama auth_set_session() directamente.
-//
-// Cookie: "<selector>:<validator>". O selector (32 hex) indexa a linha; só o
-// SHA-256 do validator (64 hex) fica na BD, por isso um dump da tabela não dá
-// para forjar um cookie. Cada utilização gasta o validator e emite outro —
-// um cookie roubado só vale até a próxima visita do dono; quando o dono volta
-// com um validator que já não bate certo, é a assinatura de uma cópia em
-// circulação, e todos os tokens da conta são revogados.
-
-const REMEMBER_COOKIE = 'fit_remember';
-const REMEMBER_DAYS    = 30;
-
-function remember_set_cookie(?string $value, int $expires = 0): void {
-    if (headers_sent()) return;
-    setcookie(REMEMBER_COOKIE, (string) $value, [
-        'expires'  => $expires,
-        'path'     => '/',
-        'secure'   => request_is_https(),
-        'httponly' => true,
-        // Lax, não Strict: um link de fora (email) não traz um cookie Strict,
-        // e a pessoa via o login outra vez apesar de ter pedido para ficar.
-        'samesite' => 'Lax',
-    ]);
-}
-
-function remember_forget_cookie(): void {
-    remember_set_cookie('', time() - 3600);
-}
-
-function remember_parse_cookie(): ?array {
-    $raw = (string) ($_COOKIE[REMEMBER_COOKIE] ?? '');
-    if ($raw === '' || substr_count($raw, ':') !== 1) return null;
-    [$selector, $validator] = explode(':', $raw, 2);
-    if (strlen($selector) !== 32 || !ctype_xdigit($selector)) return null;
-    if (strlen($validator) !== 64 || !ctype_xdigit($validator)) return null;
-    return ['selector' => $selector, 'validator' => $validator];
-}
-
-// Chamar depois de um login bem sucedido, só quando a pessoa pediu para ficar.
-function remember_issue(PDO $pdo, int $userId): void {
-    if ($userId <= 0) return;
-    $selector  = bin2hex(random_bytes(16));
-    $validator = bin2hex(random_bytes(32));
-    $expires   = time() + REMEMBER_DAYS * 86400;
-    try {
-        $pdo->prepare(
-            "INSERT INTO remember_tokens (user_id, selector, validator_hash, expires_at, last_ip, user_agent)
-             VALUES (?, ?, ?, ?, ?, ?)"
-        )->execute([
-            $userId, $selector, hash('sha256', $validator), date('Y-m-d H:i:s', $expires),
-            client_ip(), mb_substr((string) ($_SERVER['HTTP_USER_AGENT'] ?? ''), 0, 255),
-        ]);
-    } catch (Throwable $e) {
-        // Um login válido nunca deve falhar por causa disto.
-        error_log('[remember] issue failed: ' . $e->getMessage());
-        return;
-    }
-    remember_set_cookie($selector . ':' . $validator, $expires);
-    if (random_int(0, 19) === 0) remember_prune($pdo);
-}
-
-// Repõe a sessão a partir do cookie, se houver um válido. Não redirecciona.
-function remember_resume(PDO $pdo): void {
-    if (!empty($_SESSION['user_id'])) return;
-    $cookie = remember_parse_cookie();
-    if ($cookie === null) return;
-
-    try {
-        $st = $pdo->prepare("SELECT * FROM remember_tokens WHERE selector = ? LIMIT 1");
-        $st->execute([$cookie['selector']]);
-        $row = $st->fetch(PDO::FETCH_ASSOC) ?: null;
-    } catch (Throwable $e) {
-        error_log('[remember] lookup failed: ' . $e->getMessage());
-        return;
-    }
-
-    if ($row === null) {
-        remember_forget_cookie();
-        return;
-    }
-
-    if (!hash_equals((string) $row['validator_hash'], hash('sha256', $cookie['validator']))) {
-        error_log('[remember] validator mismatch for user ' . (int) $row['user_id'] . ' — a revogar todos os tokens da conta');
-        remember_forget_user($pdo, (int) $row['user_id']);
-        remember_forget_cookie();
-        return;
-    }
-
-    if (strtotime((string) $row['expires_at']) <= time()) {
-        remember_delete($pdo, (string) $row['selector']);
-        remember_forget_cookie();
-        return;
-    }
-
-    $st = $pdo->prepare("SELECT * FROM users WHERE id = ? AND is_active = 1 LIMIT 1");
-    $st->execute([(int) $row['user_id']]);
-    $user = $st->fetch(PDO::FETCH_ASSOC) ?: null;
-    if ($user === null) {
-        remember_forget_user($pdo, (int) $row['user_id']);
-        remember_forget_cookie();
-        return;
-    }
-
-    auth_set_session($user);
-    $_SESSION['_remembered'] = true;
-    remember_rotate($pdo, (string) $row['selector']);
-}
-
-function remember_rotate(PDO $pdo, string $selector): void {
-    $validator = bin2hex(random_bytes(32));
-    $expires   = time() + REMEMBER_DAYS * 86400;
-    try {
-        $pdo->prepare("UPDATE remember_tokens SET validator_hash = ?, expires_at = ?, last_ip = ? WHERE selector = ?")
-            ->execute([hash('sha256', $validator), date('Y-m-d H:i:s', $expires), client_ip(), $selector]);
-    } catch (Throwable $e) {
-        error_log('[remember] rotate failed: ' . $e->getMessage());
-        return;
-    }
-    remember_set_cookie($selector . ':' . $validator, $expires);
-}
-
-function remember_delete(PDO $pdo, string $selector): void {
-    try { $pdo->prepare("DELETE FROM remember_tokens WHERE selector = ?")->execute([$selector]); }
-    catch (Throwable $e) { error_log('[remember] delete failed: ' . $e->getMessage()); }
-}
-
-// Chamar no logout e ao mudar a palavra-passe — corta qualquer cookie roubado.
-function remember_forget_user(PDO $pdo, int $userId): void {
-    try { $pdo->prepare("DELETE FROM remember_tokens WHERE user_id = ?")->execute([$userId]); }
-    catch (Throwable $e) { error_log('[remember] forget_user failed: ' . $e->getMessage()); }
-}
-
-function remember_prune(PDO $pdo): void {
-    try { $pdo->exec("DELETE FROM remember_tokens WHERE expires_at < NOW()"); }
-    catch (Throwable $e) { /* accessório */ }
-}
diff --git a/config/functions_user.php b/config/functions_user.php
index dec0840..c18cba2 100644
--- a/config/functions_user.php
+++ b/config/functions_user.php
@@ -1,8 +1,11 @@
 <?php
-// ─── Users: lookup, authentication, registration, password reset ─────────────
-// This install owns its identity. Passwords live in `users.password_hash`;
-// views/auth/login.php is a real form and require_login() (config/auth.php)
-// bounces unauthenticated visitors there. Nothing is delegated to a hub.
+// ─── Users: lookup, registration, password reset ─────────────────────────────
+// This install owns its identity — passwords live in `users.password_hash` —
+// but auditoria 2026-09-24 ponto 1.3 moved credential verification and
+// session establishment to shared/platform-tools/functions_auth.php
+// (auth_attempt()/auth_login(), wired in config/db.php). What is left here is
+// fitme-specific: registration, backoffice user creation, password reset
+// tokens and their emails — none of which has a shared equivalent.
 //
 // parse_user_agent() lives in config/functions.php; db_get_user() /
 // db_get_all_staff() / db_get_active_admins() live in config/functions_db.php
@@ -26,46 +29,28 @@ function admin_exists(PDO $pdo): bool {
 }
 
 // ─── Authentication ──────────────────────────────────────────────────────────
+//
+// Credential verification is now auth_attempt($pdo, $email, $password) from
+// shared/platform-tools/functions_auth.php — same account-enumeration timing
+// defence and transparent rehash, one implementation instead of two. Login
+// itself (session + audit "auth.login" + last_login_at/ip stamp) is
+// auth_login($pdo, $user) from the same file. See views/auth/login.php.
+//
+// last_login_ua has no shared equivalent (functions_auth.php only tracks
+// last_login/last_ip) and is still fitme's own — stamped separately, right
+// after auth_login(), by fit_stamp_login_ua() below.
 
-// Hash bcrypt (custo 12) de uma password aleatória descartada — só serve para
-// igualar o tempo de resposta quando a conta não existe.
-const AUTH_DUMMY_HASH = '$2y$12$luPhZpP46FkyufPCM1d8Gu4lPNS3A/I0gSvoBiNEL3lZAauMkuzH2';
-
-// Verifies credentials and stamps the login trail. Returns the user row on
-// success, null on bad email / bad password / inactive account / no password
-// set. Callers must not leak which of the four it was.
-function auth_login(PDO $pdo, string $email, string $password): ?array {
-    $stmt = $pdo->prepare(
-        "SELECT * FROM users WHERE email = ? AND is_active = 1 AND password_hash IS NOT NULL LIMIT 1"
-    );
-    $stmt->execute([strtolower(trim($email))]);
-    $user = $stmt->fetch(PDO::FETCH_ASSOC);
-
-    if (!$user) {
-        // Sem conta, verifica na mesma contra um hash de referência: um bcrypt
-        // de custo 12 demora dezenas de ms, e responder mais depressa quando o
-        // email não existe diria a quem tenta quais emails têm conta.
-        password_verify($password, AUTH_DUMMY_HASH);
-        return null;
-    }
-    if (!password_verify($password, $user['password_hash'])) {
-        return null;
-    }
-
-    // Transparently upgrade hashes when PHP's default algorithm/cost moves on.
-    if (password_needs_rehash($user['password_hash'], PASSWORD_DEFAULT)) {
-        $pdo->prepare("UPDATE users SET password_hash = ? WHERE id = ?")
-            ->execute([password_hash($password, PASSWORD_DEFAULT), $user['id']]);
-    }
-
-    $ip = client_ip();
+// Stamps the user-agent of the browser that just logged in. Best-effort:
+// shown in views/user/index.php ("last seen from …") but never worth failing
+// a login over.
+function fit_stamp_login_ua(PDO $pdo, int $userId): void {
     $ua = substr($_SERVER['HTTP_USER_AGENT'] ?? '', 0, 512) ?: null;
-    $pdo->prepare("UPDATE users SET last_login_at = NOW(), last_login_ip = ?, last_login_ua = ? WHERE id = ?")
-        ->execute([$ip, $ua, $user['id']]);
-    $user['last_login_at'] = date('Y-m-d H:i:s');
-    $user['last_login_ip'] = $ip;
-    $user['last_login_ua'] = $ua;
-    return $user;
+    try {
+        $pdo->prepare("UPDATE users SET last_login_ua = ? WHERE id = ?")
+            ->execute([$ua, $userId]);
+    } catch (Throwable $e) {
+        error_log('[auth] last_login_ua stamp failed: ' . $e->getMessage());
+    }
 }
 
 // Writes a new password hash. Shared by the reset flow, the profile page and
@@ -74,10 +59,10 @@ function auth_login(PDO $pdo, string $email, string $password): ?array {
 // take the account back.
 function auth_set_password(PDO $pdo, int $userId, string $password): void {
     $pdo->prepare("UPDATE users SET password_hash = ? WHERE id = ?")
-        ->execute([password_hash($password, PASSWORD_DEFAULT), $userId]);
+        ->execute([auth_password_hash($password), $userId]);
     // Uma password nova invalida qualquer «manter sessão iniciada» antigo —
     // sem isto, um cookie roubado antes da mudança continuava a entrar depois.
-    remember_forget_user($pdo, $userId);
+    auth_remember_forget_user($pdo, $userId);
     $self = (int) ($_SESSION['user_id'] ?? 0) === $userId;
     audit($self ? 'auth.password_change' : 'user.password_set', [
         'target_type' => 'user', 'target_id' => $userId,
@@ -123,7 +108,7 @@ function auth_register_client(PDO $pdo, array $data): array {
         }
         $pdo->prepare(
             "UPDATE users SET name = ?, phone = COALESCE(?, phone), password_hash = ?, is_active = 1 WHERE id = ?"
-        )->execute([$name, $phone, password_hash($data['password'], PASSWORD_DEFAULT), $row['id']]);
+        )->execute([$name, $phone, auth_password_hash($data['password']), $row['id']]);
         audit('user.register', ['target_type' => 'user', 'target_id' => (int) $row['id'], 'target_label' => $name,
                                 'summary' => 'Registo que reclamou uma conta de cliente sem palavra-passe', 'actor' => null]);
         return ['id' => (int) $row['id']];
@@ -139,7 +124,7 @@ function auth_register_client(PDO $pdo, array $data): array {
             $name,
             $email,
             $phone,
-            password_hash($data['password'], PASSWORD_DEFAULT),
+            auth_password_hash($data['password']),
             !empty($data['marketing_consent']) ? 1 : 0,
         ]);
     } catch (PDOException $e) {
@@ -164,7 +149,7 @@ function auth_create_sysadmin(PDO $pdo, string $name, string $email, string $pas
     $stmt->execute([
         $name,
         strtolower(trim($email)),
-        password_hash($password, PASSWORD_DEFAULT),
+        auth_password_hash($password),
     ]);
     $id = (int) $pdo->lastInsertId();
     audit('user.create', ['target_type' => 'user', 'target_id' => $id, 'target_label' => $name,
@@ -193,7 +178,7 @@ function _create_backoffice_user(PDO $pdo, string $role, string $name, string $e
             $name,
             strtolower(trim($email)),
             $phone ?: null,
-            password_hash($password, PASSWORD_DEFAULT),
+            auth_password_hash($password),
             $role,
         ]);
     } catch (PDOException $e) {
diff --git a/database/migration_20260925_shared_auth_attempts.sql b/database/migration_20260925_shared_auth_attempts.sql
new file mode 100644
index 0000000..638645e
--- /dev/null
+++ b/database/migration_20260925_shared_auth_attempts.sql
@@ -0,0 +1,34 @@
+-- ─── auth_attempts: torna-a conforme com o throttle do platform-tools ────────
+-- Auditoria 2026-09-24, ponto 1.3: a app passa a usar o auth partilhado
+-- (shared/platform-tools/functions_auth.php) em vez do seu próprio login/
+-- sessão/roles. Ver config/db.php ('auth' => 'shared').
+--
+-- Esta tabela já existia (migration_20260913_local_auth.sql) com o formato do
+-- throttle PRÓPRIO da app (config/functions_throttle.php: `ip` + `scope`,
+-- cobre login/registo/recuperação). O throttle partilhado
+-- (auth_throttle_check/hit em functions_auth.php) espera `identifier` + `ip`
+-- e falharia (INSERT INTO auth_attempts (identifier, ip) ...) com um erro de
+-- SQL — silenciosamente engolido pelo try/catch do throttle partilhado, que
+-- por desenho falha aberto e deixaria de bloquear ninguém.
+--
+-- Decisão: a app CONTINUA a usar só o seu próprio throttle (login+registo+
+-- recuperação, dois níveis IP+conta) — não passa a chamar
+-- auth_throttle_check()/auth_throttle_hit() em lado nenhum, para não duplicar
+-- a defesa contra o mesmo formulário com duas contagens diferentes. Esta
+-- migração só torna a TABELA conforme com o que o platform_conformance()
+-- (config/db.php, 'conformance' => 'report') verifica, para o relatório de
+-- saúde ficar limpo e para deixar a porta aberta a usar o throttle partilhado
+-- no futuro sem precisar de outra migração.
+--
+-- `identifier` e `success` são aditivos, com omissão — invisíveis para o
+-- INSERT/SELECT do throttle próprio, que continua a nomear só `ip`+`scope`.
+-- `scope` passa a ter omissão (era NOT NULL sem omissão) porque é a única
+-- coluna que o INSERT do throttle partilhado não preenche; sem omissão esse
+-- INSERT falhava em modo estrito.
+--
+-- Safe to re-run (IF NOT EXISTS é extensão do MariaDB).
+
+ALTER TABLE `auth_attempts` ADD COLUMN IF NOT EXISTS `identifier` VARCHAR(190) NOT NULL DEFAULT '' AFTER `id`;
+ALTER TABLE `auth_attempts` ADD COLUMN IF NOT EXISTS `success` TINYINT(1) NOT NULL DEFAULT 0 AFTER `attempted_at`;
+ALTER TABLE `auth_attempts` MODIFY COLUMN `scope` VARCHAR(20) NOT NULL DEFAULT '';
+ALTER TABLE `auth_attempts` ADD INDEX IF NOT EXISTS `idx_identifier_time` (`identifier`, `attempted_at`);
diff --git a/views/auth/login.php b/views/auth/login.php
index 75ece4d..84469b7 100644
--- a/views/auth/login.php
+++ b/views/auth/login.php
@@ -1,6 +1,16 @@
 <?php
 // Local login form. This install owns its passwords (users.password_hash);
-// there is no identity provider in front of it.
+// there is no identity provider in front of it. Credential check and session
+// establishment go through shared/platform-tools/functions_auth.php
+// (auth_attempt()/auth_login()) since auditoria 2026-09-24 ponto 1.3 — see
+// config/db.php for the connection and the reasoning on auth_attempts.
+//
+// The throttle below is still fitme's own (config/functions_throttle.php),
+// not the shared auth_throttle_check()/auth_throttle_hit(): it already covers
+// login (two tiers: per-IP and per-account) plus register/forgot_password,
+// which the shared throttle doesn't touch at all, so switching only the login
+// scope over would mean running two different throttles for the same form
+// with no reduction in code. Kept as one system.
 //
 // Carries through ?return_to=/path, set by require_login(), so the visitor
 // lands back on the page they originally asked for.
@@ -54,13 +64,16 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
     throttle_record($pdo, 'login');
     throttle_record($pdo, 'login_acct', $acct);
 
-    $user = auth_login($pdo, $_POST['email'] ?? '', $_POST['password'] ?? '');
+    $user = auth_attempt($pdo, $_POST['email'] ?? '', $_POST['password'] ?? '');
     if ($user) {
-        auth_set_session($user);
+        // auth_login() (shared) regenerates the session, stamps
+        // last_login_at/ip and audits "auth.login" itself — no need to also
+        // call the old auth_set_session()/audit() pair here.
+        auth_login($pdo, $user);
+        fit_stamp_login_ua($pdo, (int) $user['id']);
         if (!empty($_POST['remember'])) {
-            remember_issue($pdo, (int) $user['id']);
+            auth_remember_issue($pdo, (int) $user['id']);
         }
-        audit('auth.login', ['target_type' => 'user', 'target_id' => (int) $user['id'], 'target_label' => (string) $user['name']]);
         header('Location: ' . base_url($destination($user['role'])));
         exit;
     }
diff --git a/views/auth/logout.php b/views/auth/logout.php
index 71574ab..215d942 100644
--- a/views/auth/logout.php
+++ b/views/auth/logout.php
@@ -1,25 +1,18 @@
 <?php
 // Ends the local session. Nothing to coordinate with an identity provider —
-// this install owns its own sessions.
+// this install owns its own sessions. auth_logout() (shared) audits
+// "auth.logout" (before it wipes $_SESSION), clears the session and its
+// cookie — same steps this file used to do by hand.
 
 require __DIR__ . '/../../config/db.php';
 require __DIR__ . '/../../config/functions.php';
 
-if (!empty($_SESSION['user_id'])) {
-    audit('auth.logout', ['target_type' => 'user', 'target_id' => (int) $_SESSION['user_id']]);
+if (auth_check()) {
     // Só o token deste browser, não toda a conta: sair aqui não deve expulsar
     // a pessoa de outro dispositivo onde pediu para ficar.
-    $cookie = remember_parse_cookie();
-    if ($cookie !== null) remember_delete($pdo, $cookie['selector']);
+    auth_remember_clear($pdo);
 }
-remember_forget_cookie();
-$_SESSION = [];
-// Drop the cookie too, so the browser doesn't keep presenting a dead id.
-if (ini_get('session.use_cookies')) {
-    $p = session_get_cookie_params();
-    setcookie(session_name(), '', time() - 42000, $p['path'], $p['domain'], $p['secure'], $p['httponly']);
-}
-session_destroy();
+auth_logout();
 
 header('Location: ' . base_url('views/auth/login.php?loggedout=1'));
 exit;
diff --git a/views/auth/register.php b/views/auth/register.php
index f84b5c8..816884b 100644
--- a/views/auth/register.php
+++ b/views/auth/register.php
@@ -51,7 +51,10 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
             // login form with credentials they just typed.
             $user = db_get_user($pdo, (int) $res['id']);
             if ($user) {
-                auth_set_session($user);
+                // auth_login() (shared) — same primitive views/auth/login.php
+                // uses, so a fresh registration and a normal login leave the
+                // session/audit trail in the same shape.
+                auth_login($pdo, $user);
                 header('Location: ' . base_url(post_login_destination($user['role'])));
                 exit;
             }