fix: update TemplateResponse to Starlette 0.41 signature

Starlette 0.41.x removed the old TemplateResponse(name, context) API.
Switch to the new TemplateResponse(request, name, context) signature,
which is the only supported form in Starlette >= 0.41.

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

app/ui/routes.py

@@ -22,7 +22,7 @@ def setup_templates(t: Jinja2Templates) -> None:
 
 def _tmpl(name: str, request: Request, ctx: dict) -> HTMLResponse:
     assert templates is not None
-    return templates.TemplateResponse(name, {"request": request, **ctx})
+    return templates.TemplateResponse(request, name, ctx)
 
 
 def _lag_str(ts: datetime | None) -> str: