feat: add analytics visibility settings and export functionality

- Added `analytics_visibility` column to `rooms` table to control who can view analytics data.
- Updated analytics routes to check visibility settings before allowing access and export of analytics data.
- Implemented export functionality for analytics in CSV, XLSX, and PDF formats.
- Enhanced `AnalyticsList` component to include export options for analytics entries.
- Updated room detail page to allow setting analytics visibility when creating or editing rooms.
- Added translations for new analytics visibility options and export messages.

server/config/database.js

@@ -802,6 +802,11 @@ export async function initDatabase() {
     `);
   }
 
+  // ── Analytics visibility setting ────────────────────────────────────────
+  if (!(await db.columnExists('rooms', 'analytics_visibility'))) {
+    await db.exec("ALTER TABLE rooms ADD COLUMN analytics_visibility TEXT DEFAULT 'owner'");
+  }
+
   // ── Default admin (only on very first start) ────────────────────────────
   const adminAlreadySeeded = await db.get("SELECT value FROM settings WHERE key = 'admin_seeded'");
   if (!adminAlreadySeeded) {