Vendor platform-tools: everything this site runs is now in one repo

shared/platform-tools was a git submodule. On this branch it is a plain
directory of tracked files, frozen at ea3616abae30106df283e73a3e2f9e5bb0e6ae90
— the same commit fotografia.andmore.pt pins. Contents are byte-identical to
that tree, verified blob by blob.

The submodule caused every deployment failure this site has had:

  - .gitmodules named no `branch`, so the update fell back to
    refs/remotes/origin/HEAD — a ref a plain server-side clone never writes.
    "Atualizar submódulo" failed with "Unable to find refs/remotes/origin/HEAD
    revision in submodule path".
  - Its URL was http://, which the origin answers with 523.
  - This install is deployed by uploading files, and a submodule is invisible
    to that. The tree moved forward while shared/platform-tools stayed on the
    old pin, config/functions_secrets.php died on a missing compat_secrets.php,
    and the whole site — public pages included — went down.

Each of those was separately fixable. Together they mean a second repository
nobody can see from the deployment path, gating whether the first one boots. A
plain directory deploys like every other file and cannot fall out of step.

The cost is that platform-tools updates no longer arrive by bumping a pin; they
are a copy-over-and-commit. shared/platform-tools/VENDORED.md records the
upstream SHA, the procedure, and which four files differ from upstream in line
endings only (social/*.js, .css, functions_publications.php — CRLF upstream,
normalised to LF here; content otherwise identical).

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

shared/platform-tools/functions_changelog.php

@@ -0,0 +1,39 @@
+<?php
+// ─── Changelog reader ────────────────────────────────────────────────────────
+// Reads the repository CHANGELOG.md and exposes the most recent version entry,
+// so the backoffice can show "Versão X — what changed" without a DB round-trip.
+// The file is versioned with the code, so it updates automatically on git pull.
+
+/**
+ * Return the latest CHANGELOG.md entry.
+ *
+ * Expected format:
+ *   ## v2.2 — Adicionado pagamentos parciais
+ *   - primeira alteração
+ *   - segunda alteração
+ *
+ * @return array{version: ?string, changes: string[]}
+ */
+function changelog_latest(): array {
+    $file = dirname(__DIR__, 2) . '/CHANGELOG.md';
+    if (!is_file($file)) return ['version' => null, 'changes' => []];
+
+    $lines = @file($file, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
+    if ($lines === false) return ['version' => null, 'changes' => []];
+
+    $version = null;
+    $changes = [];
+    foreach ($lines as $line) {
+        if (preg_match('/^##\s+(.+)$/', $line, $m)) {
+            if ($version === null) {
+                $version = trim($m[1]);
+                continue;
+            }
+            break; // reached the next version entry
+        }
+        if ($version !== null && str_starts_with(ltrim($line), '-')) {
+            $changes[] = ltrim(ltrim($line), '- ');
+        }
+    }
+    return ['version' => $version, 'changes' => $changes];
+}