build(ci): align dev postgres service with PG branch (glibc image, localhost bind)

Keeps the aggregation merge conflict-free: both branches now carry the
identical block.

Claude-Session: https://claude.ai/code/session_01NrWVk8oMToieU6y3yDtYpY

Author: dnplkndll

docker-compose.yml

@@ -174,15 +174,17 @@ services:
     volumes:
       - data-s3:/data:rw
 
-  # PostgreSQL development instance.
+  # PostgreSQL development instance. Same glibc image as postgres_test —
+  # the alpine (musl) variant has different collation behavior, and there is
+  # a collation_test.go that would pass on one and fail on the other.
   postgres:
-    image: postgres:16-alpine
+    image: ${FLEET_POSTGRES_IMAGE:-postgres:16}
     environment:
       POSTGRES_USER: fleet
       POSTGRES_PASSWORD: insecure
       POSTGRES_DB: fleet
     ports:
-      - "5433:5432"
+      - "127.0.0.1:5433:5432"
     volumes:
       - postgres-persistent-volume:/var/lib/postgresql/data