feat: extract MediaController, wire into Dispatcher, delete media.php

app/public/admin/actions/export-db.php

@@ -0,0 +1,29 @@
+<?php
+/**
+ * Export the whole SQLite database as a file download.
+ *
+ * Thin dispatcher — delegates to ExportController.
+ */
+require_once __DIR__ . "/../../../bootstrap.php";
+require_once __DIR__ . '/../../../src/AdminAuth.php';
+AdminAuth::requireLogin();
+
+require_once APP_ROOT . '/src/Controllers/ExportController.php';
+$controller = ExportController::create();
+
+$dbPath = $controller->getDatabasePath();
+
+if (!file_exists($dbPath)) {
+    http_response_code(500);
+    exit('Base de données introuvable.');
+}
+
+$filename = 'posterg-db-' . date('Y-m-d') . '.sqlite';
+
+header('Content-Type: application/octet-stream');
+header('Content-Disposition: attachment; filename="' . $filename . '"');
+header('Content-Length: ' . filesize($dbPath));
+header('Cache-Control: no-cache, must-revalidate');
+
+readfile($dbPath);
+exit;