feat: SDD workflow — test sync, song generation + validation, ReaScript hybrid pipeline

- compose-test-sync: fix 3 failing tests (NOTE_TO_MIDI, DrumLoopAnalyzer mock, section name)
- generate-song: CLI wrapper + RPP validator (6 structural checks) + 4 e2e tests
- reascript-hybrid: ReaScriptGenerator + command protocol + CLI + 16 unit tests
- 110/110 tests passing
- Full SDD cycle (propose→spec→design→tasks→apply→verify) for all 3 changes

.sdd/changes/archive/2026-05-03-compose-test-sync/ARCHIVE.md

@@ -0,0 +1,65 @@
+# Archive: compose-test-sync
+
+**Archived**: 2026-05-03  
+**Status**: Complete — all 90 tests pass
+
+---
+
+## Summary
+
+Test-only sync change. Fixed 3 failing tests to match the new compose.py API after the great rewrite. No compose.py files were modified.
+
+---
+
+## Specs Synced
+
+| Domain | Action | Details |
+|--------|--------|---------|
+| None | N/A | Test-only change — no spec-level capabilities modified |
+
+No main specs updated (test-only change, no capability modification per proposal).
+
+---
+
+## Files Changed
+
+| File | Change | Description |
+|------|--------|-------------|
+| `tests/test_section_builder.py` | Modified | Replaced `root_to_midi` with `NOTE_TO_MIDI` dict lookup |
+| `tests/test_render_cli.py` | Modified | Removed obsolete `DrumLoopAnalyzer` mock |
+| `tests/test_compose_integration.py` | Modified | Fixed section name from `"verse"` to `"chorus"`, removed `analysis` arg |
+
+---
+
+## Tasks Completed
+
+All 4 phases completed per `tasks.md`:
+
+- ✅ 1.1–1.3: Replaced `root_to_midi` with `NOTE_TO_MIDI["A"]` + octave offset formula
+- ✅ 2.1–2.5: Removed `DrumLoopAnalyzer` patch and related dead code
+- ✅ 3.1–3.2: Changed section name to `"chorus"`, removed unused `analysis` line
+- ✅ 4.1–4.2: Confirmed 90/90 tests pass, no scripts/ files modified
+
+---
+
+## Verification
+
+- **Test result**: 90/90 tests passing (`pytest tests/ -q`)
+- **Scripts modified**: None confirmed via `git diff --name-only scripts/`
+- **Change scope**: Test-only, no compose.py changes
+
+---
+
+## Archive Contents
+
+- `proposal.md` ✅
+- `design.md` ✅
+- `tasks.md` ✅
+
+No `spec.md` existed for this change (test-only, no spec-level capabilities).
+
+---
+
+## SDD Cycle Complete
+
+The change has been fully planned, implemented, verified, and archived. Ready for the next change.