fix(docker): fix healthchecks for PostgREST, Storage, Studio

- PostgREST: replace wget healthcheck with TCP socket check — PostgREST
  v12 is a minimal image without wget/curl
- All services: add start_period to healthchecks to avoid premature
  unhealthy marking during initial startup

docker-compose.yml

@@ -134,10 +134,11 @@ services:
       PGRST_JWT_SECRET: ${JWT_SECRET}
       PGRST_DB_USE_LEGACY_GUCS: "false"
     healthcheck:
-      test: ["CMD-SHELL", "wget --no-verbose --tries=1 --spider http://localhost:3000/ || exit 1"]
+      test: ["CMD-SHELL", "head -c0 </dev/tcp/localhost/3000 || exit 1"]
       interval: 10s
       timeout: 5s
       retries: 5
+      start_period: 15s
 
   # =====================================================
   # Supabase Realtime
@@ -208,6 +209,7 @@ services:
       interval: 10s
       timeout: 5s
       retries: 5
+      start_period: 15s
 
   # =====================================================
   # Supabase imgproxy (image transformations)
@@ -266,6 +268,7 @@ services:
       interval: 10s
       timeout: 5s
       retries: 5
+      start_period: 30s
 
   # =====================================================
   # Supabase Inbucket (Email testing)