feat: Add chat embeds v1

Youtube and Website metadata embeds

electron/migrations/1000000000005-AddLinkMetadata.ts

@@ -0,0 +1,11 @@
+import { MigrationInterface, QueryRunner } from 'typeorm';
+
+export class AddLinkMetadata1000000000005 implements MigrationInterface {
+  async up(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(`ALTER TABLE "messages" ADD COLUMN "linkMetadata" text`);
+  }
+
+  async down(queryRunner: QueryRunner): Promise<void> {
+    // SQLite does not support DROP COLUMN; column is nullable and harmless.
+  }
+}