feat(caldav): implement CalDAV support with token management and calendar operations

server/config/database.js

@@ -649,6 +649,36 @@ export async function initDatabase() {
     `);
   }
 
+  // ── CalDAV tokens ────────────────────────────────────────────────────────
+  if (isPostgres) {
+    await db.exec(`
+      CREATE TABLE IF NOT EXISTS caldav_tokens (
+        id SERIAL PRIMARY KEY,
+        user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+        token TEXT UNIQUE NOT NULL,
+        name TEXT NOT NULL,
+        created_at TIMESTAMP DEFAULT NOW(),
+        last_used_at TIMESTAMP DEFAULT NULL
+      );
+      CREATE INDEX IF NOT EXISTS idx_caldav_tokens_user_id ON caldav_tokens(user_id);
+      CREATE INDEX IF NOT EXISTS idx_caldav_tokens_token ON caldav_tokens(token);
+    `);
+  } else {
+    await db.exec(`
+      CREATE TABLE IF NOT EXISTS caldav_tokens (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        user_id INTEGER NOT NULL,
+        token TEXT UNIQUE NOT NULL,
+        name TEXT NOT NULL,
+        created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+        last_used_at DATETIME DEFAULT NULL,
+        FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
+      );
+      CREATE INDEX IF NOT EXISTS idx_caldav_tokens_user_id ON caldav_tokens(user_id);
+      CREATE INDEX IF NOT EXISTS idx_caldav_tokens_token ON caldav_tokens(token);
+    `);
+  }
+
   // ── Default admin (only on very first start) ────────────────────────────
   const adminAlreadySeeded = await db.get("SELECT value FROM settings WHERE key = 'admin_seeded'");
   if (!adminAlreadySeeded) {