fix: use fixed port 3010 for production postgrest, remove dynamic allocation

Dynamic port leasing was the root cause of all the "address already in use"
failures. Production now always uses 3010; dev still uses 3001. No more
.postgrest-port file, no more port scanning loop, no more race conditions.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docker-compose.yml

@@ -36,7 +36,7 @@ services:
       PGRST_OPENAPI_MODE: disabled
       PGRST_DB_EXTRA_SEARCH_PATH: public,extensions
     ports:
-      - "127.0.0.1:${POSTGREST_HOST_PORT:-3011}:3001"
+      - "127.0.0.1:${POSTGREST_HOST_PORT:-3010}:3001"
 
   minio:
     image: minio/minio:latest