docs: add local troubleshooting tips

docs/TROUBLESHOOTING_LOCAL.md

@@ -0,0 +1,44 @@
+# Local troubleshooting
+
+This page lists common issues when running TIPS locally and quick ways to resolve them.
+
+## Docker compose: ports already in use
+
+Symptoms:
+- `bind: address already in use`
+Fix:
+- Stop conflicting containers or change the mapped ports in `docker-compose*.yml`.
+
+## Postgres connection failures
+
+Symptoms:
+- application logs show `connection refused` or auth errors
+Fix:
+- Confirm the DB container is healthy.
+- Ensure `.env` values match the compose service settings.
+- If you changed credentials, recreate containers:
+  - `docker compose down -v`
+  - `docker compose up -d`
+
+## Migrations / schema mismatch
+
+Symptoms:
+- runtime errors on missing columns / tables
+Fix:
+- Run the project’s migration step (if provided), or reset the local database volume.
+
+## Kafka not reachable
+
+Symptoms:
+- timeouts when publishing/consuming events
+Fix:
+- Verify Kafka is up and the bootstrap URL matches your local config.
+- Restart Kafka + dependent services if needed.
+
+## UI not updating
+
+Symptoms:
+- UI loads but shows stale data
+Fix:
+- Hard refresh the browser.
+- Verify the backend services are running and returning fresh responses.