Fix login form rendering inside dashboard on session expiry

HTMX polls /api/devices/live every 3s; when the session expires, the
302 redirect to /login was followed by HTMX and the login page HTML was
injected into the live-devices div. Use HX-Redirect header instead so
HTMX performs a full-page navigation to the login page.

Author: atsyplikhin

packages/device-connect-server/device_connect_server/portal/app.py

@@ -29,6 +29,10 @@ async def auth_middleware(request: web.Request, handler):
 
     session = await _get_session(request)
     if not session.get("username"):
+        if request.headers.get("HX-Request"):
+            resp = web.Response(status=200)
+            resp.headers["HX-Redirect"] = "/login"
+            return resp
         raise web.HTTPFound("/login")
 
     request["user"] = session