Redesign chord symbols around a shared grammar

[Copilot]

Chord parsing and formatting could disagree about token boundaries, implied tensions, and slash basses, causing symbols to change meaning on round-trip. Replace the substring parser and concatenated formatter with a grammar-driven reader and canonical writer.

• Reader/writer: Consume the complete symbol, enforce token order, reject duplicate or conflicting modifiers, and emit canonical extension, suspension, alteration, add, omission, and bass order.
• Chord semantics: Preserve altered extension stacks, add MinorSharpFive, and update chord tones and roman-numeral analysis.
• Compatibility: Continue reading legacy forms such as C79, Csus47, and C6add9.
• Coverage/docs: Add grammar cases, exhaustive round trips for expressible chords, and document the grammar in the music guide.

Chord.Parse("C7add13").ToString(); // "C7add13"
Chord.Parse("C13b9").ToString();   // "C13b9"
Chord.Parse("Cm#5").ChordTones();  // minor third, augmented fifth

• Fixes Redesign chord symbols: one grammar for Chord.Parse and Chord.ToString (fixes #300 #322 #336 #340 #341 #344 #345 #346 #358) #360

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
95.6% Coverage on New Code
0.0% Duplication on New Code

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