Split the web UI into a page per section

The dashboard was a single route that swapped section components via a
`section` state field. Convert it to the App Router's multi-page model so
each left-nav selection is its own route (/, /repositories, /agents,
/schedules, /approvals, /servers, /activity, /shared, /login), making the
pages modular and independently updatable.

- Move the token gate + store provider + sidebar into a persistent frame
  (AppFrame + Shell) rendered by the root layout, so auth, the polling
  loop, and shared state survive client-side navigation.
- Sidebar items are now <Link> routes; the active item and the store's
  polled section are derived from the URL (lib/nav).
- Each section gets an app/<section>/page.tsx; Runs stays at root and keeps
  its full-height split layout, the rest render in the shared scroll frame.
- Emit per-route index.html (trailingSlash) so the FastAPI StaticFiles
  mount serves clean slash-terminated URLs with no SPA rewrite.
- Regenerate the bundled static export.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PsAeGVadULRzPhV2PRDttM

frontend/app/page.tsx

@@ -1,49 +1,10 @@
-/* Root page: token gate → dashboard. Client-only; the exported HTML is a shell and every
- * byte of data is fetched by the browser from the authed API after the token is supplied. */
+/* Runs — the inbox and the app's landing page (root route). Rendered inside the shared
+ * shell from the root layout; unlike the scrollable sections it owns its own split layout,
+ * so it renders directly into main with no outer scroll wrapper. */
 "use client";
 
-import { useCallback, useEffect, useState } from "react";
-import { DashboardProvider } from "@/components/store";
-import { Dashboard } from "@/components/Dashboard";
-import { TokenGate } from "@/components/TokenGate";
+import { RunsSection } from "@/components/sections/RunsSection";
 
-const TOKEN_KEY = "handler_token";
-
-export default function Home() {
-  const [token, setToken] = useState<string | null>(null);
-  const [error, setError] = useState("");
-
-  // Read the stored token after mount (localStorage is client-only).
-  useEffect(() => {
-    const stored = window.localStorage.getItem(TOKEN_KEY);
-    if (stored) setToken(stored);
-  }, []);
-
-  const saveToken = useCallback((t: string) => {
-    window.localStorage.setItem(TOKEN_KEY, t);
-    setError("");
-    setToken(t);
-  }, []);
-
-  const signOut = useCallback(() => {
-    window.localStorage.removeItem(TOKEN_KEY);
-    setToken(null);
-  }, []);
-
-  // A 401 from any call clears the token and re-prompts with an error.
-  const onUnauthorized = useCallback(() => {
-    window.localStorage.removeItem(TOKEN_KEY);
-    setToken(null);
-    setError("Invalid token — please try again.");
-  }, []);
-
-  if (!token) {
-    return <TokenGate error={error} onSubmit={saveToken} />;
-  }
-
-  return (
-    <DashboardProvider token={token} onUnauthorized={onUnauthorized}>
-      <Dashboard onSignOut={signOut} />
-    </DashboardProvider>
-  );
+export default function RunsPage() {
+  return <RunsSection />;
 }