feat(dashboard,cli): update-check frequency, GitHub star button, more resizable modals

Update-check frequency (end-to-end)
- Add `updateCheckFrequency: "manual" | "on-startup" | "daily" | "weekly"`
  to GlobalSettings (default: "daily").
- Backend `performUpdateCheck` honors the frequency: TTL = day/week,
  `manual` returns cache or empty without hitting npm, `on-startup`
  refreshes once per process lifetime then serves cache. `/refresh`
  route forces network regardless.
- Settings → Updates surfaces a working `<select>` for the cadence,
  disabled when auto-checks are off entirely.
- Tests: 4 new cases covering ttlForFrequency mapping, weekly window,
  manual semantics, on-startup once-per-process behavior.

TUI update notice
- Read cached update result synchronously on TUI startup. When an
  update is available, render a yellow notice line on the splash and
  a colored ● next to the version in the status bar.

Settings modal header polish
- Add "Star on GitHub" pill (icon + Star + cached star count from the
  GitHub API, 1h localStorage TTL) and "Help" button (opens project
  Discussions). Both link to the Runfusion/Fusion repo.
- Star button auto-hides after the user clicks it (intent = star),
  tracked in localStorage `fusion:github-star-clicked`.
- Settings → General gets a "Show Star on GitHub button" checkbox so
  users can hide it preemptively. New global setting
  `showGitHubStarButton: boolean` (default true) gates rendering.

More resizable modals
- Task Detail modal: 85vh default, resize: both, persisted via
  useModalResizePersist (key `fusion:task-detail-modal-size`).
- Quick Chat FAB: full 8-direction resize (4 corners + 4 edges) via
  pointer-event handlers; persisted to
  `fusion:quick-chat-size-<projectId>`. Each handle has the right
  cursor + role="separator" for accessibility.

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

packages/dashboard/app/components/TaskDetailModal.css

@@ -1,4 +1,15 @@
 /* === Detail Modal === */
+.modal.task-detail-modal {
+  width: min(95vw, 800px);
+  max-width: 95vw;
+  min-width: 480px;
+  height: 85vh;
+  min-height: 480px;
+  max-height: calc(100dvh - var(--overlay-padding-top, 10vh) - 16px);
+  overflow: hidden;
+  resize: both;
+}
+
 .detail-title-row {
   display: flex;
   align-items: center;