feat: implement calendar invitation system with creation, acceptance, and management features

server/config/database.js

@@ -514,6 +514,50 @@ export async function initDatabase() {
     await db.exec('ALTER TABLE calendar_events ADD COLUMN federated_join_url TEXT DEFAULT NULL');
   }
 
+  // Calendar invitations (federated calendar events that must be accepted first)
+  if (isPostgres) {
+    await db.exec(`
+      CREATE TABLE IF NOT EXISTS calendar_invitations (
+        id SERIAL PRIMARY KEY,
+        event_uid TEXT NOT NULL,
+        title TEXT NOT NULL,
+        description TEXT,
+        start_time TIMESTAMP NOT NULL,
+        end_time TIMESTAMP NOT NULL,
+        room_uid TEXT,
+        join_url TEXT,
+        from_user TEXT NOT NULL,
+        to_user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+        color TEXT DEFAULT '#6366f1',
+        status TEXT DEFAULT 'pending' CHECK(status IN ('pending','accepted','declined')),
+        created_at TIMESTAMP DEFAULT NOW()
+      );
+      CREATE INDEX IF NOT EXISTS idx_cal_inv_to_user ON calendar_invitations(to_user_id);
+      CREATE UNIQUE INDEX IF NOT EXISTS idx_cal_inv_uid_user ON calendar_invitations(event_uid, to_user_id);
+    `);
+  } else {
+    await db.exec(`
+      CREATE TABLE IF NOT EXISTS calendar_invitations (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        event_uid TEXT NOT NULL,
+        title TEXT NOT NULL,
+        description TEXT,
+        start_time DATETIME NOT NULL,
+        end_time DATETIME NOT NULL,
+        room_uid TEXT,
+        join_url TEXT,
+        from_user TEXT NOT NULL,
+        to_user_id INTEGER NOT NULL,
+        color TEXT DEFAULT '#6366f1',
+        status TEXT DEFAULT 'pending' CHECK(status IN ('pending','accepted','declined')),
+        created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+        FOREIGN KEY (to_user_id) REFERENCES users(id) ON DELETE CASCADE,
+        UNIQUE(event_uid, to_user_id)
+      );
+      CREATE INDEX IF NOT EXISTS idx_cal_inv_to_user ON calendar_invitations(to_user_id);
+    `);
+  }
+
   // ── Default admin (only on very first start) ────────────────────────────
   const adminAlreadySeeded = await db.get("SELECT value FROM settings WHERE key = 'admin_seeded'");
   if (!adminAlreadySeeded) {