fix(demo-service): render HTML inline instead of download

- FileResponse sets Content-Disposition: attachment by default
- Switch to HTMLResponse for .html files to render in browser

home-apps/demo-service/service.py

@@ -164,6 +164,9 @@ async def site_content(path: str = "", request: Request = None):
         target = target / "index.html"
         if not target.exists():
             return HTMLResponse(AUTH_REQUIRED_HTML, status_code=404)
+    # HTML files render inline; others (CSS, JS, images) are served as files
+    if target.suffix == ".html":
+        return HTMLResponse(target.read_text())
     return FileResponse(target)
 
 @app.get("/api/sites")