Add i18n, branding, user management, health checks, and cleanup for deployment

- Multi-language support (EN/DE) with i18n engine and language files
- Configurable branding (name, subtitle, logo) in Settings
- Global default language and per-user language preference
- User management router with CRUD endpoints
- Customer status sync on start/stop/restart
- Health check fixes: derive status from container state, remove broken wget healthcheck
- Caddy reverse proxy and dashboard env templates for customer stacks
- Updated README with real hardware specs, prerequisites, and new features
- Removed .claude settings (JWT tokens) and build artifacts from tracking
- Updated .gitignore for .claude/ and Windows artifacts

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

app/main.py

@@ -9,7 +9,7 @@ from fastapi.responses import JSONResponse
 from fastapi.staticfiles import StaticFiles
 
 from app.database import init_db
-from app.routers import auth, customers, deployments, monitoring, settings
+from app.routers import auth, customers, deployments, monitoring, settings, users
 
 # ---------------------------------------------------------------------------
 # Logging
@@ -50,6 +50,7 @@ app.include_router(settings.router, prefix="/api/settings", tags=["Settings"])
 app.include_router(customers.router, prefix="/api/customers", tags=["Customers"])
 app.include_router(deployments.router, prefix="/api/customers", tags=["Deployments"])
 app.include_router(monitoring.router, prefix="/api/monitoring", tags=["Monitoring"])
+app.include_router(users.router, prefix="/api/users", tags=["Users"])
 
 # ---------------------------------------------------------------------------
 # Static files — serve the frontend SPA