skills/sheet-music: Record chords as syllable markers and compute chord columns, lyric widening and word splits in the generator

[JoshuaVSherman]

Summary

• src/sheet-music/types.ts: update ChordLyricLine documentation to reflect inline chord markers (e.g. re[C/E]member), preserving optional legacy fields for backward compatibility; export RenderedLine and ParseLineOptions interfaces.
• src/sheet-music/builder.ts: implement inline chord marker parsing, chord syntax validation (CHORD_REGEX, isValidChordToken), and guard error handling for performance annotations ([Everybody!], [hold]), malformed brackets ([], [G, G]), and adjacent markers ([G][C]).
• src/sheet-music/builder.ts: compute chord column positions, lyric widening at markers with - word splitting for intra-word syllables and whitespace expansion for inter-word gaps, and reserved width based on Math.max(guitar.length, bass.length).
• src/sheet-music/builder.ts: implement automatic line re-breaking at ~75 characters preferring word gaps following punctuation, keeping chords anchored to their syllables.
• src/sheet-music/builder.ts: add validateSongDefinition to fail closed with clear error identifying offending section/line on non-string lyric fields.
• test/sheet_music.test.ts: add comprehensive unit tests covering acceptance criteria 1-13 and local verification check 2 asserting C/E column matches computed column of m in member.
• deno.json: bump version from 1.38.14 to 1.38.15 per the mandatory first-commit version bump policy.

Closes #1010

How to test locally

Run the test suites locally from /home/joshua/WebJamApps/web-jam-tools:

deno task test test/sheet_music.test.ts
deno task test
deno task check
deno task lint
deno task fmt:check
deno task audit
deno task sast

Exercise the change directly:

1. Build a lyric line from re[C/E]member and verify the generated chord-line column for C/E equals the computed column of m in member (result[0].lyrics.indexOf("member")).
2. Verify [C/D]O[D]ceans rise, widens with - word splitting to chord line C/D D and lyric O - ceans rise,.
3. Verify love's [G/F] not places G/F strictly within the gap between love's and not.
4. Verify willing to pay. [Am7] [C/D] positions both chords after pay..
5. Verify [Am7b5]dat [Cm/D]da [D]ya-da! widens spaces between words.
6. Verify dual-tier layout with explicit bass [G|A] and capo 2 transposed bass [G] and [D/F#].
7. Verify lines wider than 75 characters re-break at word gaps preferring punctuation and keeping chords on their syllables.
8. Verify guard error handling: performance annotations [Everybody!] and [hold] are rejected naming the annotation field; empty [], unclosed [G, stray G], and adjacent [G][C] are rejected; non-string lyrics fields fail closed identifying the section and line.

Test evidence

Local test suite results:

$ deno task test test/sheet_music.test.ts
running 23 tests from ./test/sheet_music.test.ts
transposeNote transposes standard notes across octaves ... ok (775µs)
transposeChord handles roots, qualities, and slash chords ... ok (293µs)
transposeChordLine preserves exact character starting column alignment ... ok (316µs)
autoTransposeSong populates bass chords and keys for dual-tier capo songs ... ok (280µs)
buildSongDocument & generateSongDocxBuffer produce valid docx for dual-tier songs ... ok (41ms)
buildSongDocument & generateSongDocxBuffer produce valid docx for single-tier songs ... ok (11ms)
generate_docx CLI runs with --json and generates output file ... ok (16ms)
generate_docx CLI shows help or handles errors on invalid input ... ok (1ms)
generate_docx CLI auto-computes destination from input file path and json ... ok (9ms)
buildSongDocument supports custom legend and tempo details ... ok (7ms)
Criterion 1 & Check 2: re[C/E]member computes C/E column equal to m in member ... ok (381µs)
Criterion 2: [C/D]O[D]ceans rise, widens with ' - ' word splitting ... ok (199µs)
Criterion 3: love's [G/F] not positions G/F in the gap between words ... ok (159µs)
Criterion 4: willing to pay. [Am7] [C/D] positions both chords after pay. ... ok (167µs)
Criterion 5: [Am7b5]dat [Cm/D]da [D]ya-da! widens word spaces ... ok (395µs)
Criterion 6: Dual-tier [G|A]You say positions guitar G bold and bass A italic in same column ... ok (244µs)
Criterion 7: Dual-tier capo 2, [G]You say transposes bass to A ... ok (111µs)
Criterion 8: Dual-tier capo 2, [D/F#] transposes bass to E/G# and reserves longer chord space ... ok (188µs)
Criterion 9: Chord names [C(add2)], [D9sus], [Cmaj7/E], [Am7b5], [Cm/Eb] parse successfully ... ok (159µs)
Criterion 10: Rendered line wider than 75 characters re-breaks preferring punctuation and keeps chords on syllables ... ok (812µs)
Criterion 11: Guard outcome valid — all valid inputs parse and lay out in full document ... ok (12ms)
Criterion 12: Guard outcome invalid — performance annotations and malformed brackets rejected with named errors ... ok (1ms)
Criterion 13: Guard outcome undeterminable — non-string lyric field refused with clear line identification ... ok (481µs)

ok | 23 passed | 0 failed (124ms)

$ deno task test
ok | 2473 passed | 0 failed (1m14s)

$ deno task check
Task check deno check src/ test/

$ deno task lint
Task lint deno lint src/ test/
Checked 190 files

$ deno task fmt:check
Task fmt:check deno fmt --check src/ test/
Checked 226 files

$ deno task audit
[audit] OK — no HIGH/CRITICAL vulns and no secrets.

$ deno task sast
[sast] OK — no blocking findings.

🤖 Work by Antigravity — Gemini Flash (High)