Add SSL certificate mode: Let's Encrypt or Wildcard per NPM

Settings > NPM Integration now allows choosing between per-customer
Let's Encrypt certificates (default) or a shared wildcard certificate
already uploaded in NPM. Includes backend, frontend UI, and i18n support.

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

app/utils/config.py

@@ -31,6 +31,8 @@ class AppConfig:
     docker_network: str
     relay_base_port: int
     dashboard_base_port: int
+    ssl_mode: str
+    wildcard_cert_id: int | None
 
 
 # Environment-level settings (not stored in DB)
@@ -79,4 +81,6 @@ def get_system_config(db: Session) -> Optional[AppConfig]:
         docker_network=row.docker_network,
         relay_base_port=row.relay_base_port,
         dashboard_base_port=getattr(row, "dashboard_base_port", 9000) or 9000,
+        ssl_mode=getattr(row, "ssl_mode", "letsencrypt") or "letsencrypt",
+        wildcard_cert_id=getattr(row, "wildcard_cert_id", None),
     )