feat(ui): re-analyze CTA for legacy Session Musician runs

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Why

When a cached run shows up with transcriptionMethod: 'basic-pitch' (or any non-torchcrepe method), the Stem note draft block enters its legacy render state and shows the notice "Re-analyze for current stem-aware quality. The notes below are kept for archival." — but PR #22 left it at just words. This adds the actual button.

Behaviour

• Block A renders a "Re-analyze with stem-aware pipeline" button only in the legacy render state AND only when App passes a callback (a source File is loaded and no analysis is currently in flight).
• Clicking the button calls back up through <SessionMusicianPanel> → <AnalysisResults> → App.tsx, which fires handleStartAnalysis({ pitchNoteRequested: true }). The File state (audioFile) is retained in App across analyses, so no re-upload is required — the existing bytes are re-POSTed to /api/analysis-runs with stem-aware mode on.
• The STEM PITCH/NOTE TRANSLATION toggle is also updated to reflect the override so subsequent manual Run Analysis clicks behave consistently.

Investigation: does the backend support artifact reuse?

Read apps/backend/analysis_runtime.py. create_run takes content: bytes and stores the audio anew on every call — there's no existing API to reference a prior artifact ID. Because audioFile: File is retained in App state after analysis completes (apps/ui/src/App.tsx:225), the cleanest path is to re-POST the same File, no backend changes needed. The producer never sees an upload dialog.

Wiring

• New optional onReanalyzeWithStemAware?: () => void prop on SessionMusicianPanel.tsx and NoteDraftBlock.tsx. AnalysisResults.tsx threads it through.
• App constructs the handler as audioFile && !isAnalyzing ? () => handleStartAnalysis({ pitchNoteRequested: true }) : undefined, so the button is only rendered (and clickable) when a re-run is actually viable.
• handleStartAnalysis gains a typed overrides param. The override is read in the call to analyzeAudio, and a matching setPitchNoteTranslationRequested keeps the toggle visually in sync.

Tests

• Vitest (sessionMusicianPanel.test.ts): five new static-markup cases — legacy + callback → button renders, legacy + no callback → no button, stem-aware → no button, full-mix-fallback → no button, ran-with-no-result / requested-but-unavailable → no button. 30 panel tests pass total.
• Playwright smoke (upload-phase1-midi.spec.ts): stubs a run that returns transcriptionMethod: 'basic-pitch'. After the page renders the legacy state, asserts the button is visible, clicks it, and confirms a second POST to /api/analysis-runs fires with pitch_note_mode=stem_notes. 47 smoke tests pass total (1 skipped — live Gemini).
• No backend changes.

Base

Targets claude/thirsty-easley-faeaea (PR #22) since that's where the redesigned panel lives. Once #22 lands on main, GitHub can retarget this or I can rebase + force-push.

Plan

~/.claude/plans/re-evaluate-asa-s-session-musician-sharded-balloon.md — "Out-of-scope follow-ups" section.

🤖 Generated with Claude Code

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Verdict: APPROVE (submitted as COMMENT — GitHub blocks self-review)

Summary

Clean prop-threading addition that wires an onReanalyzeWithStemAware callback from App.tsx down through AnalysisResults → SessionMusicianPanel → NoteDraftBlock, rendering a re-run button only in the legacy render state. No backend changes. All 336 unit tests pass; the five new Vitest cases cover every relevant render-state combination, and the new Playwright smoke test confirms the second POST fires with pitch_note_mode=stem_notes.

Findings

Worth considering

• App.tsx: setPitchNoteTranslationRequested is called inside handleStartAnalysis to keep the toggle visually in sync with the override, but no test actually asserts the toggle flips. The logic is trivial so it's not a blocking gap, but if the override path is ever refactored it'll be unguarded.

• The smoke test stubs every POST's run with requestedStages.pitchNoteMode: 'stem_notes' regardless of what the first click sends. Fine for the purpose — only the second POST value is asserted — but postedPitchNoteModes[0] is never checked, so a regression in the first run's pitch_note_mode would slip through.

• type StartAnalysisOverrides is defined inside the component body just before handleStartAnalysis. Zero runtime cost (types are erased), but convention is module scope. Not a finding per the style rules, just noting it.

Test results

336 passed / 0 failed across 35 test files.

Phase boundary check

Clean. No Phase 1 measurements read, re-derived, or mutated anywhere in this diff. Phase 2/3 files untouched. The re-analyze path re-POSTs the existing audioFile with pitchNoteRequested: true through the same analyzeAudio entry point as a normal run.

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Generated by Claude Code

[slittycode]

Superseded by #29 (rebased onto main and re-opened as a new PR after PR #22 merged caused this one to auto-close).