feat(state): replace in-memory Map with SQLite-backed stateService (#59)

- Create src/services/stateService.js with get/set/delete/has API
- Create migration 004_user_states.js (chat_id PK, state_data JSON, updated_at)
- TTL of 24 hours — expired states auto-deleted
- Cleanup job runs every hour (setInterval)
- Replace src/context/userStates.js Map with async stateService proxy
- Add await to all 45 userStates.get/set/delete/has calls across 13 files
- Add initStates() call in index.js startup sequence
- All state survives bot restarts now

18 files changed, 172 insertions, 46 deletions

src/index.js

@@ -8,8 +8,11 @@ import adminHandler from './handlers/adminHandlers/adminHandler.js';
 import callbackRouter from './router/callbackRouter.js';
 import messageRouter from './router/messageRouter.js';
 
+import { initStates } from './services/stateService.js';
+
 await runMigrations();
 await cleanUpInvalidForeignKeys();
+await initStates();
 
 const logDebug = (action, functionName) => {
     logger.debug({ action, functionName }, 'Button Press');