Add frontend client for musing-ai-service

[danibsheehan]

Summary

Wires musing's frontend up to the now-live `musing-ai-service` backend: search, summarize, related pages, background indexing, and a usage indicator.

• `src/lib/aiClient.ts`: `isAiServiceConfigured()` (mirrors `isSupabaseConfigured()`'s pattern, plus requires Supabase configured since every endpoint needs a session JWT), an `AiServiceError` class, typed wrappers for all five backend endpoints. Cross-origin, per the earlier architecture correction (no same-origin proxy — see Add CORS to musing-ai-service; drop the same-origin proxy plan #93).
• `src/lib/blockPlainText.ts`: strips HTML from block content before anything goes to the AI service — mirrors `blockEditorCommands.ts`'s `isBlockHtmlVisuallyEmpty()` DOM approach.
• `src/hooks/usePageIndexing.ts`: debounces `embed-page` ~2s after a page's blocks stop changing (document pages only), mirroring `WorkspaceContext`'s 800ms remote-save debounce but longer since this costs money. Failures are logged, never surfaced.
• UI wiring, per the earlier placement discussion:
  • `PageChrome.tsx`: a Summarize button as a sibling to Export, not a third item inside it — Export's whole model is "click, download, no persistent UI," Summarize needs to show text, so it gets its own busy-state + dismissible result panel.
  • `RelatedPagesSection.tsx`: collapsed-by-default disclosure under the page header.
  • `SidebarSearch.tsx`: debounced (300ms) search input above the page tree, deduped to one result per page.
  • `AppLayout.tsx`: a compact `AiUsageBadge` pill next to the existing `RemoteSyncBadge`.
• `VITE_AI_SERVICE_URL` wired into `.env.example`, `vite-env.d.ts`, and `deploy-pages.yml`'s build env (mirrors the `VITE_SUPABASE_*` pattern exactly).

Found and fixed via `/code-review` (6 parallel finders): the three new components referenced CSS classes that were never defined anywhere in the repo (confirmed by grep) — the search dropdown would have rendered as broken inline content instead of an overlay. Added the missing `App.css` rules. Also fixed `RelatedPagesSection` swallowing fetch errors into the same empty state as "no related pages" — now shows a real error, matching how `PageChrome` already handles the same failure class for summarize/export.

Documented, not fixed: `usePageIndexing`'s debounce can reset without a real edit when `WorkspaceContext` replaces the whole snapshot (cross-tab sync, or the initial remote-fetch race) — delays indexing, never skips or corrupts it; not worth the complexity of a content-hash key for a delay-only edge case.

Coverage: thresholds hold without new component-level tests, consistent with this codebase's existing convention (`PageChrome`/`PageView`/`Sidebar`/`AppLayout` have none; only lib/hook logic is unit-tested here). `aiClient.ts` (82%) and `usePageIndexing.ts` (93%) — the actual new logic — are well covered.

Cannot verify in a browser — no browser automation tool is available in this environment. Verified instead: typecheck, lint, full test suite, production build, and that every referenced CSS class now resolves (grep-checked). A real manual click-through is still needed before merging.

Test plan

• `npx tsc -b --noEmit`, `npm run lint`, `npm run format:check` — all pass
• `npx vitest run` — 161/161 passing; coverage above thresholds
• `npm run build` — succeeds
• Manual, needs a real browser: with `VITE_AI_SERVICE_URL` unset, confirm zero AI UI renders and no console errors; with it set, confirm Summarize/Related/Search/usage badge actually work against the live service

🤖 Generated with Claude Code

[github-actions]

PR guide

Auto-generated from changed paths. Fill in Summary and How to verify in the PR description above.

Touches: app shell / routes, tests, CI / GitHub, other

Diff: 15 files changed, 908 insertions(+)

Suggested verify

• npm run lint
• npm run format:check
• npm run test:run or targeted Vitest files for the changed area
• npm run build
• Review workflow syntax and required permissions in GitHub Actions

Checklist (applies to this PR)

• No unintended secrets or local-only config committed
• Routes work with import.meta.env.BASE_URL for GitHub Pages subpath hosting
• Workflow permissions are scoped to the PR-guide behavior

Reviewer focus

• Routing, layout state, and Pages BASE_URL behavior
• Workflow event triggers, token permissions, and label/comment behavior on same-repo vs fork PRs
• Test assertions cover the behavior under review rather than only implementation details

Commits

• c91963b Add frontend client for musing-ai-service

Files by area

Area	Files
app shell / routes	6
tests	2
CI / GitHub	1
other	6

CI

Primary check: CI runs lint, Prettier format check, Vitest coverage, and build for every PR. Coverage tables are posted separately.

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[github-actions]

Unit tests (Vitest)

File	Coverage	Lines	Branches
All files	55%	62%	48%	✅
src/components/DatabaseEmbedNodeView.tsx	0%	0%	0%	✅
src/components/DatabaseTableView.tsx	0%	0%	0%	✅
src/components/SlashMenu.tsx	72%	85%	60%	✅
src/context/WorkspaceContext.tsx	25%	35%	14%	✅
src/extensions/blockIdOnBlocks.ts	75%	100%	50%	✅
src/extensions/musingDatabaseEmbed.ts	70%	90%	50%	✅
src/extensions/singleTopLevelBlock.ts	80%	100%	60%	✅
src/hooks/usePageIndexing.ts	95%	90%	100%	✅
src/lib/aiClient.ts	81%	86%	76%	✅
src/lib/blockEditorCommands.ts	42%	50%	35%	✅
src/lib/blockPlainText.ts	55%	60%	50%	✅
src/lib/editorBlockText.ts	13%	13%	14%	✅
src/lib/emojiSuggestionItems.ts	93%	100%	87%	✅
src/lib/htmlToDocx.ts	24%	31%	18%	✅
src/lib/pageToExportHtml.ts	97%	100%	94%	✅
src/lib/resolveWikiPage.ts	91%	100%	83%	✅
src/lib/slashMenuOptions.ts	57%	57%	0%	✅
src/lib/themePreference.ts	32%	25%	40%	✅
src/lib/workspaceStorage.ts	80%	81%	80%	✅
src/lib/pageDocument/blockGutterOps.ts	92%	100%	84%	✅
src/lib/pageDocument/blockIdAtSelection.ts	83%	100%	66%	✅
src/lib/pageDocument/lastBlockNeedsBelowHit.ts	91%	100%	83%	✅
src/lib/pageDocument/serializeDocToBlocks.ts	58%	69%	47%	✅
src/lib/pageDocument/slashMenuDeleteRange.ts	82%	95%	70%	✅
src/lib/pageDocument/tryDeleteEmptyTopLevelBlock.ts	87%	94%	81%	✅

Minimum allowed coverage is 0%

Generated by 🐒 cobertura-action against c91963b