fix: wait for Postgres to be ready before starting Forgejo

Adds a pg_isready healthcheck to the postgres service and upgrades the
Forgejo depends_on to condition: service_healthy, preventing the
"connection refused" crash on startup.

https://claude.ai/code/session_01FKCW3FDjNFj6jve4niMFXH

infra/docker-compose.yml

@@ -73,6 +73,11 @@ services:
       - hiy-pg-data:/var/lib/postgresql/data
       # SQL files here run once on first init (ignored if data volume already exists).
       - ./postgres-init:/docker-entrypoint-initdb.d:ro
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U $$POSTGRES_USER -d $$POSTGRES_DB"]
+      interval: 5s
+      timeout: 5s
+      retries: 10
     networks:
       - hiy-net
 
@@ -96,7 +101,8 @@ services:
     volumes:
       - forgejo-data:/data
     depends_on:
-      - postgres
+      postgres:
+        condition: service_healthy
     networks:
       - hiy-net