Refactor test database setup and add migrations

- Updated test files to use a separate test database configuration.
- Introduced a new helper module for managing test database operations.
- Added a setup file to configure the environment for tests.
- Created new database migration scripts to optimize message indexing.
- Added a sample environment file for test database configuration.

tests/setup.ts

@@ -0,0 +1,7 @@
+import process from "node:process";
+
+process.env.NODE_ENV = "test";
+
+if (process.env.TEST_DATABASE_URL) {
+  process.env.DATABASE_URL = process.env.TEST_DATABASE_URL;
+}