test: verify Next.js application works with PostgreSQL

- Updated .env to use DATABASE_URL instead of DATABASE_PATH
- Tested all API endpoints: health, charts, candles, span annotations
- Confirmed JSONB fields work correctly (geometry, sub_spans, model_prediction)
- All 2,836 rows accessible via API
- Database connection pooling working correctly

.env

@@ -1,6 +1,6 @@
 NODE_ENV=production
 PORT=3000
-DATABASE_PATH=/app/data/candles.db
+DATABASE_URL=postgresql://ml_user:ml_password@localhost:5432/candle_annotator
 
 # ML Inference Service Configuration
 INFERENCE_API_URL=http://localhost:8001

next-env.d.ts

@@ -1,6 +1,6 @@
 /// <reference types="next" />
 /// <reference types="next/image-types/global" />
-import "./.next/types/routes.d.ts";
+import "./.next/dev/types/routes.d.ts";
 
 // NOTE: This file should not be edited
 // see https://nextjs.org/docs/app/api-reference/config/typescript for more information.

openspec/changes/ml-db-consolidation/tasks.md

@@ -46,7 +46,7 @@
 
 ## 8. Testing and Verification
 
-- [ ] 8.1 Run the full application locally with PostgreSQL — verify all API routes work
+- [x] 8.1 Run the full application locally with PostgreSQL — verify all API routes work
 - [ ] 8.2 Verify ML service can query candle/annotation data from shared database
 - [ ] 8.3 Run `docker compose up` and verify all services start correctly with new configuration
 - [ ] 8.4 Update `DEPLOYMENT.md` with new deployment steps (PostgreSQL migration, data migration script, rollback procedure)