fix(ui): make Feed tab clickable — add /feed route + tabFromPath branch

Commit 1e92e7d ("move Pane to first tab") flipped the URL default from
feed → pane but missed two follow-ups:

  1. App.tsx has explicit routes for every tab except `/s/:name/feed`.
     When the user clicked Feed, navigate("/s/<name>/feed") matched the
     catch-all `<Navigate to="/" replace />` and yanked them back to
     the dashboard — the visible symptom was "Feed tab unclickable".

  2. tabFromPath had no `endsWith("/feed")` branch (it relied on the
     implicit default that used to be feed). Even if the route had
     existed, the tab indicator would have stayed on Pane.

Add the route and the branch. No other changes.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: aksOps

ui/src/App.tsx

@@ -26,6 +26,7 @@ import { AuthGate } from "@/routes/AuthGate";
 const router = createBrowserRouter([
   { path: "/", element: <Dashboard /> },
   { path: "/s/:name", element: <Dashboard /> },
+  { path: "/s/:name/feed", element: <Dashboard /> },
   { path: "/s/:name/checkpoints", element: <Dashboard /> },
   { path: "/s/:name/pane", element: <Dashboard /> },
   { path: "/s/:name/subagents", element: <Dashboard /> },

ui/src/routes/SessionDetail.tsx

@@ -41,6 +41,7 @@ type TabKey =
   | "meta";
 
 function tabFromPath(pathname: string): TabKey {
+  if (pathname.endsWith("/feed")) return "feed";
   if (pathname.endsWith("/checkpoints")) return "checkpoints";
   if (pathname.endsWith("/pane")) return "pane";
   if (pathname.endsWith("/subagents")) return "subagents";