Send mail locally again: message_queue + PHPMailer over SMTP

Outbound email was relayed to the hub's /notify endpoint, so this install had
no SMTP configuration of its own and no way to see what had been sent. Bring
delivery back in-house, following the fotografia.andmore.pt stack rather than
inventing a second shape for it.

  - Submodule bumped 603ff84 -> ea3616a, the pin fotografia already uses. That
    is what provides functions_mail.php (shared transport), functions_settings.php
    (platform_smtp_config + encrypted settings) and compat_secrets.php. Verified
    no function-name collisions with this repo's own config/functions_settings.php:
    platform-tools namespaces everything platform_*.

  - PHPMailer 7.1.1 vendored at vendor/PHPMailer/src/. platform_mail_available()
    looks for exactly this hand-vendored layout before falling back to composer's
    autoloader, so the host needs no shell and no composer install. LGPL-2.1
    license text included.

  - config/functions_queue.php replaced: was a thin facade over the hub relay,
    now fotografia's real queue. Rows are claimed atomically, retried with
    exponential backoff up to max_attempts, and park in 'failed' with the real
    SMTP rejection in last_error.

  - SMTP resolution matches the fleet: .env wins for the SMTP_* constants, while
    the actual send goes through platform_smtp_config($pdo), which is DB-first.
    That ordering is deliberate -- the database is the half an operator can
    change from the backoffice without shell access. Empty SMTP_HOST falls back
    to PHP mail().

  - Sistema -> Comunicações (views/sysadmin/comms.php): credentials plus a live
    SMTP connection test and a verdict on what would happen to a message sent
    right now. Secret-valued settings are write-only in the form and encrypted
    at rest (AES-256-GCM, key from .env, never in the DB dump). Which keys count
    as secret is platform_settings_is_secret()'s decision, not a list kept here.

  - Sistema -> Mensagens (views/sysadmin/messages.php): the queue monitor.
    Filters, per-message detail with last_error, and retry/cancel/archive.
    Retry flushes inline so the operator sees the outcome immediately.

  - cron.php drains the queue every 5 minutes, serialised with a lock file, and
    runs retention once a day. Over HTTP it answers 404 until CRON_TOKEN is set
    to something other than replace_me. Deliberately not a copy of fotografia's
    cron: the session-reminder, download-digest and photo-archive steps have no
    modules here and would be dead code.

  - config/functions_notify_client.php deleted, and ANDMORE_ID_URL with it --
    the hub relay was its only caller.

Verified without a database: PHP lint across the tree; PHPMailer builds a full
MIME message with RFC 2047 UTF-8 subject encoding from the three vendored files;
platform_mail_available() finds them; platform_mail_make() returns a correctly
configured mailer; the diagnosis states report Operacional / Não configurado.
NOT verified: the settings encryption round-trip -- this machine's PHP has no
openssl extension, so platform_secret_key() returns null and values pass through
in clear. The code degrades safely (stores the value rather than losing it) and
the Comunicações page warns when the key is unavailable.

Deployment: apply database/migration_20260913_message_queue.sql, set SMTP in
Comunicações or .env, set APP_SECRET_KEY, and schedule cron.php.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

database/migration_20260913_message_queue.sql

@@ -0,0 +1,42 @@
+-- Local outbound message queue.
+--
+-- Added when fitme3070 stopped relaying mail through the hub's /notify endpoint
+-- and went back to sending its own, PHPMailer over SMTP. Mirrors the
+-- fotografia.andmore.pt table so the shared queue code ports unchanged.
+--
+-- Safe to re-run.
+
+CREATE TABLE IF NOT EXISTS `message_queue` (
+  `id`              INT(11) NOT NULL AUTO_INCREMENT,
+  `channel`         ENUM('email','sms','whatsapp') NOT NULL DEFAULT 'email',
+  `status`          ENUM('pending','sending','sent','failed','cancelled') NOT NULL DEFAULT 'pending',
+  `to_user_id`      INT(11) DEFAULT NULL,
+  `to_address`      VARCHAR(255) NOT NULL,
+  `to_name`         VARCHAR(150) DEFAULT NULL,
+  `reply_to`        VARCHAR(190) DEFAULT NULL,
+  `subject`         VARCHAR(255) DEFAULT NULL,
+  `body`            LONGTEXT NOT NULL,
+  `alt_body`        TEXT DEFAULT NULL,
+  `context_type`    VARCHAR(50) DEFAULT NULL,
+  `context_id`      INT(11) DEFAULT NULL,
+  `scheduled_for`   DATETIME DEFAULT NULL,
+  `attempts`        INT(11) NOT NULL DEFAULT 0,
+  `max_attempts`    INT(11) NOT NULL DEFAULT 3,
+  `next_attempt_at` DATETIME DEFAULT NULL,
+  `last_error`      TEXT DEFAULT NULL,
+  `created_by`      INT(11) DEFAULT NULL,
+  `sent_at`         DATETIME DEFAULT NULL,
+  `created_at`      DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  `updated_at`      DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  `deleted_at`      DATETIME DEFAULT NULL,
+  PRIMARY KEY (`id`),
+  -- The drainer's hot query: pending/failed rows whose turn has come.
+  KEY `idx_mq_drain` (`status`, `next_attempt_at`, `scheduled_for`),
+  KEY `idx_mq_created` (`created_at`),
+  KEY `idx_mq_context` (`context_type`, `context_id`),
+  KEY `idx_mq_deleted` (`deleted_at`)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
+-- No foreign key on to_user_id / created_by: messages outlive the accounts they
+-- were sent to, and the delivery history is worth more than the referential
+-- tidiness. The Monitor page tolerates a missing user.