feat: guna MySQL external — host.docker.internal (dev) & 172.17.200.16 (prod)

- Buang service db dan volume dbdata dari compose files
- dev: extra_hosts host.docker.internal:host-gateway → capai MySQL Windows host
- prod: IP terus 172.17.200.16, tiada extra_hosts diperlukan
- .env.docker: DB_HOST=host.docker.internal dengan nota untuk production
- entrypoint.sh: default DB_HOST → host.docker.internal

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

.env.docker

@@ -28,7 +28,9 @@ LOG_LEVEL=debug
 
 # ── Database ──────────────────────────────────────────────────────────────────
 DB_CONNECTION=mysql
-DB_HOST=db                # nama service dalam docker-compose.yml
+# DEV (Windows):  DB_HOST=host.docker.internal  ← MySQL pada host Windows
+# PRODUCTION:     DB_HOST=172.17.200.16          ← MySQL server external
+DB_HOST=host.docker.internal
 DB_PORT=3306
 DB_DATABASE=ecert_mbip
 DB_USERNAME=ecert