feat(frontend): palette search, screen-reader announcements, page-level Escape, calmer polling and scrolling

[dovvnloading]

Problem

Nine frontend defects, mostly accessibility and navigation:

• The command palette could only find the eight newest chats, and its theme item turned "system" into "dark".
• A screen reader was never told that a response started, finished, stopped or failed.
• Escape stopped a response only while the composer had focus, and useHotkey re-registered every render, fired on every auto-repeat and during IME composition, and matched AltGr (Ctrl+Alt) as Ctrl, so AltGr+K opened the palette while typing.
• Scripted smooth scrolling ignored prefers-reduced-motion.
• The plain and virtualized transcripts disagreed on "at the bottom" (80px vs Virtuoso's 4px), and following a streamed reply assigned scrollTop on every frame under a scroll-behavior: smooth container, restarting an animation each time.
• Message times showed only the clock time.
• Code blocks could not wrap, GFM task items showed a bullet and a checkbox, and a dropped image left no trace.
• Dead code sat in api/, hooks/ and the stylesheet.
• Polling restarted (and fired an extra request) whenever its interval changed, asked a ready llama.cpp runtime every two seconds, and never slowed down when the backend was failing.

Root cause

Each was a local omission, confirmed against the current code before changing it. The ones worth stating: the palette rendered chats.slice(0, 8), and cmdk can only filter rendered items; useVisiblePolling put intervalMs in its effect dependencies and ran the callback at the top of the effect, so any interval change was also "start polling"; both poll callbacks swallowed their own errors, so nothing upstream could see a failure; and cmdk derives an item's identity from its text, so untitled chats (all "New Chat") share one highlight.

Change

One commit per concern:

• FE-19 formatMessageTime(value, now) adds month and day for an earlier day this year and the year for an earlier year (viewer's locale and zone); the <time> carries the full date and time in title.
• FE-20 A Wrap toggle beside Copy, one preference for every block, remembered in localStorage (session-only if storage is blocked); task-list CSS; images are still never loaded but a placeholder names the alt text with the source in title.
• FE-16 useVisiblePolling re-arms its timer on an interval change without running the callback; runs once on being enabled; counts a throw or rejection as a failure and, with backoff, doubles the wait from the third consecutive failure up to 30 s, resetting on success. llama.cpp is polled every 2 s only while the runtime is downloading, starting or stopping (or a reply is generating) and every 15 s otherwise; one check follows each generation that ends. The execution poll now sees its failures (the callers that refresh after an action keep swallowing them).
• FE-18 / FE-40 One NEAR_END_PX for both transcripts (atBottomThreshold on Virtuoso); scrollToBottom(behavior) is instant by default and smooth only for "Jump to latest"; a small useMediaQuery hook makes both the smooth jump and Virtuoso's smooth follow fall back under reduced motion.
• FE-39 usePageEscape stops a running response from anywhere on the page, but not when something already handled the key, a dialog/menu/listbox is open, focus is in another text field, or the key is a repeat/composition/modified. useHotkey holds its handler in a ref, ignores repeats and composition, and requires Alt to be up for a modifier combo.
• FE-37 ResponseAnnouncer: a visually hidden polite status that says "Response started", "Response complete, N tokens", "Response stopped" or "Response failed", driven by the chat store so an outcome the stream host publishes is heard whichever page was showing. The transcript itself stays non-live, and nothing is announced per token.
• FE-22 With text typed, all chats are searched (scored, best first, at most 50 shown, debounced 120 ms so a long history is not scored on every key), heading "Chats" instead of "Recent chats", query forgotten on close. Chat rows use the id as the cmdk value and the title as a keyword (see Limits), so several chats with the same title are separate reachable rows. The theme item cycles system, light, dark and shows the next one.
• FE-13 Removed: useRafBatchedText (the stream hook has its own batcher), the client methods diagnostics, shutdown, executionStatus, startCodeExecution, startScratchCompute, startRecipeImageTransform, stageAttachment, streamExecution with the two tests that only exercised them, ChatPage's second copy of the generation defaults, and the CSS for .rounded-picker, .input-with-icon, .field-value, .gguf-download-status, .execution-task-capabilities. streamJob loses a stray void. A new test fails for any tokens.css class no component names (with a checked allow-list).
• The screenshot script tools/screenshots/capture_showcase.mjs pressed "Toggle theme"; it now presses "Change theme" and reaches light and back to dark through the new cycle.

Compatibility and rollback

No API, contract or persisted-data change. New localStorage key cortex.codeWrap (a boolean). The palette item is renamed "Toggle theme" to "Change theme" (two App tests and the screenshot script updated). Deleted client methods mirror backend routes that still exist. Everything reverts with git revert of the individual commits; none depends on another except that the FE-22 commit needs nextThemePreference from lib/theme.ts, which it adds.

Checks

Run from the worktree, after the final rebase onto origin/main unless noted:

• npm ci, npm run typecheck, npm run lint: clean.
• npm test -- --run: 62 files, 858 tests passed (baseline before this branch: 58 files, 741 tests).
• npm run test:coverage: passed (857 tests, measured before the final test-only commit), statements 89.55%, branches 84.43%, functions 88.4%, lines 92.06% (floors 84/79/83/87, not changed).
• npx playwright test on command-palette, virtualized-transcript, accessibility, theme, chat and composer: 26 passed. Run before the last three commits (the screenshot script, the post-generation status check, and the real-overlay test) and not repeated after. attachments, chat-groups, execution and real-api were not run.
• Pre-push hook (scripts/check.ps1, quick tier) on both pushes: all 11 checks passed (ruff, actionlint/zizmor, mypy, pytest, artifact-boundary review, contract drift, tsc, eslint, vitest). It ran on Python 3.14.0 only; no Python file changed, so the 3.10/3.12/3.13 matrix was not exercised.
• Each new behaviour test was run against the previous source and failed there: FE-19/20 (19 failures across the three files), FE-16 (9 hook and 2 App tests), FE-18/40 (7), FE-37/39 (16), FE-22 (16), the CSS orphan test (it named 11 classes). The tests that pass on either side are the negative ones (for example "leaves Escape to an open dialog") and reports an approval that went through even when the refresh after it fails, which is a guard for the new split of the execution refresh.

Security / data-loss / concurrency

• Images are still never fetched: the placeholder is text, and the source appears only in a title.
• Escape only stops a response (the kept answer is unaffected, and the stop path already ignores a late stop). It is not sent from text fields or over dialogs, so it cannot discard an edit.
• The announcer never reads message content or the failure reason, only a status and a token count, and does not duplicate the composer's alert.
• A polling callback that rejects is now always handled, never an unhandled rejection. Stale results of an old effect instance are ignored once it is torn down (stopped).
• No logging was added.

Limits

• Not verified with a real screen reader or inside the desktop WebView2 shell: the live region, the instant scroll behaviour and reduced motion are tested through jsdom, a mocked matchMedia and Playwright's Chromium. capture_showcase.mjs was only syntax-checked; it needs the staged showcase server.
• FE-39 is partial: the new shortcuts (new chat, focus composer, toggle sidebar) and key hints on palette items are not done. FE-37 is partial: the shortcut that focuses the last assistant message (and tabIndex={-1} on articles) is not done. Both were outside the scope given for this change.
• FE-13 is partial. Kept on purpose: cancelJob and listHuggingFaceGGUFFiles (the download-cancel and file-listing work will use them), createChat and health (client.test.ts uses them as request vehicles), useUiStore.dismissToast (toast work), and LocalSetup/SystemStatusCard (no importer today, but the new-chat screen work may use them; README.md contains no sentence about a setup screen, so there was nothing to remove there). The theme-* class on AppShell is unused, but dropping its prop means editing the very long <AppShell ...> line in App.tsx, which parallel chat-deletion work also edits. ChatPage's duplicate generation defaults were the only remaining one; MessageComposer already imported the shared table.
• The palette's chat filter uses cmdk's own scoring (defaultFilter) through a custom filter that scores chat rows on their title keyword rather than their id value. Debouncing means a match for an older chat appears about 120 ms after typing pauses, during which "No results." is suppressed. The 50-result cap is not announced to the user.
• The overlay check in usePageEscape is a role selector (dialog, alertdialog, menu, listbox); a future overlay without one of those roles would need adding. A test with the real Base UI dialog and the cmdk palette pins the two that exist.
• Mutation testing was not run (not available here). The coverage floors were not raised.

Plan item: FE-22, FE-37, FE-39, FE-40, FE-18, FE-19, FE-20, FE-13, FE-16

🤖 Generated with Claude Code

[dovvnloading]

Merged origin/main into this branch (merge commit b58393d5, plus two follow-up commits; branch head 78dfa029). Plain merge, no rebase or force-push. frontend/package-lock.json is unchanged against main (git diff origin/main -- frontend/package-lock.json is empty), and git diff origin/main --stat lists only this pull request's files.

How each conflict was resolved

Only two files conflicted textually; both were resolved by keeping both sides.

• frontend/src/app/runtimeAvailability.test.ts: kept this branch's llamacppPollInterval suite (FE-16) and main's "while the model inventory is loading" suite (feat(frontend): pick GGUF files from a repository, cancel and resume model downloads #314/feat(frontend): interaction polish A - toasts, chat delete with Undo, approval expiry, memory panel, new-chat guide, drafts #318). runtimeAvailability.ts auto-merged: main's inventoryLoading / inventory-loading reason and this branch's llamacppPollInterval and poll constants coexist.
• frontend/src/styles/tokens.css: kept main's new rules (GGUF file picker, toast message/action/dismiss, new-chat guide, memory undo, expired task state, connection-pending). The one line this branch had already deleted as dead, .gguf-download-status, was dropped again, because main's extracted GGUFDownloadForm still does not use it (the orphan-CSS test from FE-13 confirms).

Semantic checks on the files that merged cleanly

• Command palette (FE-22): App.tsx passes main's visibleChats to CommandPalette, so a chat hidden by the Undo window is not offered and comes back after Undo. This was not pinned by any test, so I added one (below).
• Theme cycle (FE-22): toggleTheme uses nextThemePreference on top of main's settings save; AppShell gets the theme prop alongside main's visibleChats.
• Announcer (FE-37) and toasts: generation failures never raise a toast in main (the reason is in the composer's alert), and the toasts main added are separate events, so the announcer and the toasts already read once each. Added tests that pin that.
• Page-wide Escape (FE-39) and main's toast: main's Undo toast is a status with a focusable Undo button, and closing the toast is what sends the delete, so Escape must not act on it. The page-wide Escape already yielded to dialog, alertdialog, menu, listbox (which covers main's delete confirmation and the model picker) and text fields; it did not yield to focus inside a toast. It now does: ToastProvider's region carries data-keeps-escape and usePageEscape ignores an Escape whose target is inside it. Nothing else about the toast changed (I deliberately did not make Escape dismiss a toast, because dismissing an Undo toast commits the delete).
• Reduced motion and at-bottom (FE-40, FE-18): main did not touch MessageList; ChatPage merged cleanly and still calls the shared scroll rule, with jumpToLatest the only smooth scroll. Existing MessageList and ChatPage.renderCost tests cover it.
• Polling (FE-16): useModelJobs follows model jobs over the job event stream, not through useVisiblePolling, so the calmer runtime polling cannot starve it. App.modelJobs.test.tsx (which selects a GGUF model, so the runtime poll is active) and App.pollRender.test.tsx both pass on the merged tree.

Tests covering both pull requests' behaviour

• frontend/src/app/App.paletteDelete.test.tsx (new): palette recent list and search omit a chat during its Undo window, offer it again after Undo, and still omit it after the delete is sent.
• frontend/src/features/chat/ChatPage.a11y.test.tsx (extended): with the real ToastProvider, Escape on a focused Undo button neither stops the response nor touches the toast, and stops the response from anywhere else; the announcer and an error toast are each read once (announcer stays a polite status, the error toast and composer alert are the only alerts); a status toast does not enter the announcer.
• frontend/src/hooks/usePageEscape.test.ts: the hook ignores a notification target and takes Escape elsewhere.
• frontend/src/app/runtimeAvailability.test.ts: both suites, side by side.
• Existing suites from both sides that exercise the merged files: App.chatDelete, App.drafts, App.modelJobs, App.pollRender, ToastProvider, AppShell, CommandPalette, MessageList, orphanCss.
• Mutation check on the two new behaviours: passing unfiltered chats to the palette, and removing the notification check from usePageEscape, each fail the new tests (3 tests failed under the mutants, all pass restored).
• One existing test was hardened, not the behaviour: "leaves Escape to another text field" focused its field before the composer took focus back after sending, and failed once under load; it now waits for that first (same approach as focusThePage).

Checks run (from frontend/ unless noted)

• npm ci, npm run typecheck, npm run lint: clean.
• npm test -- --run: 77 files, 1047 tests passed (was 76 files, 1041 tests on the plain merge, before the added tests).
• npm run test:coverage: passed, floors held (statements 91.29%, branches 86.66%, functions 90.53%, lines 93.34%).
• Repo root: python -m ruff check backend tests tools main.py app_factory.py scripts passed; python -m mypy reported no issues in 97 source files.
• Pre-push hook (full quick tier) passed, 11 of 11 checks, including backend pytest, contracts, artifact-boundary review, and the vitest run above.
• Not run: Playwright e2e (not part of the quick tier).

Rollback: revert the two follow-up commits (b28320a5, 78dfa029) to return to the plain textual merge, or revert the merge commit to return to the branch as reviewed.