feat(editor): Tempo Map legibility S-pack — HUD legend, unmapped tail, barline copy

[ChrisBeWithYou]

Charrette UX P6 — four legibility fixes to Tempo Map mode (the "S-pack"). No new commands.

1. HUD legend

A colour key at the right end of the tempo HUD strip — mapped · selected · locked · suggested · unmapped — using the exact pole colours _tempoMapDraw paints (slate / amber / emerald / dashed-amber ghost / hatch). Module-const data + a shared diagonal-hatch helper, so it rides the existing draw pass with no per-frame allocation. It only draws when it clears the guidance text to its left, so the two never collide on a narrow canvas (the legend simply drops out).

2. Unmapped tail

The recording past the last confirmed downbeat carries no fitted tempo (design doc: that tail is Unmapped). It now gets the doc-mandated hatched wash + "Unmapped" label in the grid, drawn under the notes/poles so they stay legible.

3. Lock copy correction

The old status — "global tempo re-fits will hold this beat" — read as if you had to lock a barline to keep an edit. You don't; manual edits always persist. New shared copy (LOCK_TOOLTIP + _lockStatusTextPure):

Lock: hold this barline's time through automatic re-fits (Fit tempo, Suggest, Modulate). Your manual edits are always kept — locking is not needed to save them.

Applied to the right-click item's tooltip and the S-key status line.

4. "sync point" → "barline"

User-facing "sync point" wording retired for "barline" (inspector hints, delete titles, lock/status messages). "sync point" stays only as internal/export vocabulary (code comments, the GoPlayAlong importer's own format term).

Tests & verification

• tests/tempo_map_guidance.test.mjs gains cases pinning the corrected lock copy (accurate, contains no "sync point") and the inspector "barline" strings — all fail on main. The existing HUD-text pins are unchanged (that pure already said "barline").
• Legend + tail are canvas draws, verified live on the testbed: pixel-sampled the HUD strip and found the exact legend swatch colours (emerald/amber/slate); the "Unmapped" label + hatch render at the song's end.
• npm test 114 green, npm run lint 0 errors (3 pre-existing warnings = main's ratchet).

Second PR of the tempo-mapping track (TEMPO-MAPPING-PR-PROMPTS.md, PR 2). Independent of PR 1 (#218); the pair (2,3) can land in either order.

🤖 Generated with Claude Code

Summary by CodeRabbit

• New Features

  • Added a clear tempo-map legend for grid states, with matching pole colors.
  • Added a hatched “Unmapped” tail region with an “Unmapped” label when applicable.

• Improvements

  • Updated tempo-map guidance and tooltips to use “barline” terminology instead of “sync point”.
  • Refined lock/unlock messaging, including clearer wording about edit persistence through re-fits.
  • Improved tempo-map drawing behavior to prevent overlapping guidance text and updated delete restrictions copy.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: ab8c7e6b-1dd2-46f3-b444-5e6a9b28548d

📥 Commits

Reviewing files that changed from the base of the PR and between 7171293 and 32998df.

📒 Files selected for processing (2)

• src/tempo.js
• tests/tempo_map_guidance.test.mjs

🚧 Files skipped from review as they are similar to previous changes (1)

• src/tempo.js

---

📝 Walkthrough

Walkthrough

Tempo Map rendering gains a color legend and hatched unmapped-tail visualization. Inspector, deletion, tap-tempo, and lock messaging now use “barline” terminology, with exported lock-copy helpers and tests covering the revised UI text.

Changes

Tempo Map legibility and copy

Layer / File(s)	Summary
Tempo HUD legend and unmapped tail src/tempo.js	Adds a pole-colour legend, collision-aware HUD placement, hatch styling, and an “Unmapped” tail from the last confirmed downbeat to the grid or audio end.
Barline and lock UX copy src/tempo.js	Updates inspector, deletion, context-menu, and tap-tempo messages to “barline”, and centralizes exported lock tooltip and status text helpers.
Copy validation and changelog tests/tempo_map_guidance.test.mjs, CHANGELOG.md	Tests revised lock and barline wording, deletion guidance, selection state, and source literals; the changelog documents the Tempo Map updates.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Possibly related PRs

• got-feedBack/feedBack-plugin-editor#73: Touches the same Tempo Map inspector terminology and UI state.
• got-feedBack/feedBack-plugin-editor#138: Touches the Tempo Map locking UX and handler flow.
• got-feedBack/feedBack-plugin-editor#215: Touches the same Tempo Map drawing and HUD logic.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 70.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the main Tempo Map legibility updates: HUD legend, unmapped tail, and barline wording changes.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feat/editor-tempomap-legend

---

_{Comment @coderabbitai help to get the list of available commands.}

[coderabbitai]

🧹 Nitpick comments (1)

src/tempo.js (1)

59-115: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Cover the new canvas branches with render tests.

The supplied tests validate copy helpers but do not exercise hatch rendering, legend collision/omission, or unmapped-tail clipping. Add canvas-mock cases for narrow and wide HUDs plus partially off-screen tails to protect these visual behaviors.

Also applies to: 242-269

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@src/tempo.js` around lines 59 - 115, Add canvas-mock render tests covering
_tempoHatchRect clipping for partially off-screen unmapped tails, and
_tempoDrawLegend behavior on both wide canvases and narrow canvases where the
legend must be omitted due to guidance overlap. Assert the relevant canvas
operations and state changes, while preserving existing copy-helper test
coverage.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@src/tempo.js`:
- Around line 59-115: Add canvas-mock render tests covering _tempoHatchRect
clipping for partially off-screen unmapped tails, and _tempoDrawLegend behavior
on both wide canvases and narrow canvases where the legend must be omitted due
to guidance overlap. Assert the relevant canvas operations and state changes,
while preserving existing copy-helper test coverage.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 46561be2-acd7-4376-93d9-546e992484c1

📥 Commits

Reviewing files that changed from the base of the PR and between 2a764a1 and 7171293.

📒 Files selected for processing (3)

• CHANGELOG.md
• src/tempo.js
• tests/tempo_map_guidance.test.mjs