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.

drizzle/migrations/0005_optimize-message-index.sql

@@ -0,0 +1,3 @@
+CREATE INDEX IF NOT EXISTS "idx_messages_guild_created_deleted" ON "messages" USING btree ("guild_id","created_at","deleted_at","id");--> statement-breakpoint
+CREATE INDEX IF NOT EXISTS "idx_messages_channel_ai_status_created" ON "messages" USING btree ("channel_id","ai_status","created_at","id");--> statement-breakpoint
+CREATE INDEX IF NOT EXISTS "idx_messages_thread_ai_status_created" ON "messages" USING btree ("thread_id","ai_status","created_at","id");

drizzle/migrations/meta/_journal.json

@@ -29,6 +29,13 @@
       "when": 1780079000000,
       "tag": "0003_ai_moderation_review_guardrails",
       "breakpoints": true
+    },
+    {
+      "idx": 5,
+      "version": "7",
+      "when": 1780218363790,
+      "tag": "0005_optimize-message-index",
+      "breakpoints": true
     }
   ]
 }