Add sender_did to chat messages and new chat tables

Introduces a migration to add a sender_did column to the chat_messages table and creates new tables for chat_device_bundles, chat_inbox, and chat_one_time_keys. Updates related API routes and adds a script for sender DID migration. These changes support device-based messaging and improved chat security.

scripts/add-sender-did.ts

@@ -0,0 +1,9 @@
+import { db } from '../src/db';
+
+async function main() {
+  await db.execute(`ALTER TABLE chat_messages ADD COLUMN IF NOT EXISTS sender_did text;`);
+  console.log('Added sender_did column to chat_messages');
+  process.exit(0);
+}
+
+main();