docs: record Sprint 9 post-deploy dismiss-bug fix across all 6 running docs

Sprint 9 (commit 6e386ba) shipped a working OnboardingTour but a
broken dismiss path: clicking X / Skip / Esc / "Got it" did
nothing. Root cause: useOnboarding().reset() was wired to the
dismiss handler at App.tsx, but reset() does the inverse of
dismiss — it clears the localStorage key and flips isComplete to
FALSE, so the tour re-rendered, the early-return did not fire,
and the dialog stayed visible. Fix: commit 1562929 split the
dismiss and reset paths into two distinct callbacks (onComplete
and onReset). User confirmed browser smoke passes.

This commit updates the 6 running docs that track Sprint 9:

- .agent/plan.md — S9.4.1 sub-task (post-deploy fix) added.
- .agent/context.md — D9 (root cause + fix) + Q4 (Vitest?) added.
- Review/sprint9-verification.md — full post-deploy fix section
  appended (root cause, fix, post-fix verification, lessons).
- Review/handoff-ui-audit.md — Sprint 9 status banner + Last
  updated footer updated to reference the fix commit.
- fix-ui-audit.md — T3.4.1 sub-task added under the T3.4
  verification gate.
- docs/HANDOFF.md — post-deploy fix paragraph added to the
  Sprint 9 section.

All 6 docs now reflect the post-deploy reality. No code changes.

docs/HANDOFF.md

@@ -338,6 +338,8 @@ Trust the tests. Trust the live runs. Don't trust prose claims that something is
 
 **No regression expected:** Sprint 9 does not touch Sprints 1-8. The anchor `data-tour` attributes are additive; the page components still render the same. The KeyboardShortcuts hook (Sprint 5) is mounted in `App.tsx` and unaffected. The react-query error handler (Sprint 4) is unaffected.
 
+**Post-deploy fix (2026-06-05, commit `1562929`):** user reported the X / Skip / Esc / "Got it" buttons did not dismiss the tour. Root cause: `App.tsx` wired the dismiss handler to `useOnboarding().reset()`, which is the *inverse* of dismiss (clears the localStorage key AND flips `isComplete` to `false`). Fix: split into two distinct callbacks — `onComplete` (dismiss) and `onReset` (re-show). User confirmed browser smoke passes after the fix. Full root-cause + lessons in `Review/sprint9-verification.md` (Post-deploy fix section).
+
 ### Sprint 10 — "Deny Forever" on Recipes (user-driven) — COMMITTED 2026-06-05
 
 **User direction (2026-06-05):** "Proceed with the next phase in the redesign. Also add a phase to include a 'Deny Forever' button in the Recipes endpoint."