feat: NPM remote mode for cross-machine deployments

- Add npm_remote setting: when enabled, proxy forwards to server_ip with
  published host ports instead of Docker container names
- Deployer looks up assigned host port via InspectContainerPort in remote mode
- Auto-remove stale containers with same name before creating new ones
- Add Remote NPM toggle with warning on NPM settings page
- DB migration + schema for npm_remote column

internal/store/models.go

@@ -63,6 +63,7 @@ type Settings struct {
 	DNSProvider          string `json:"dns_provider"`
 	CloudflareAPIToken   string `json:"cloudflare_api_token"`
 	CloudflareZoneID     string `json:"cloudflare_zone_id"`
+	NpmRemote           bool   `json:"npm_remote"`
 	ProxyProvider       string `json:"proxy_provider"`
 	TraefikEntrypoint   string `json:"traefik_entrypoint"`
 	TraefikCertResolver string `json:"traefik_cert_resolver"`