feat: support ScoreKit sound textures

[jamiesun]

Summary

• support ScoreKit 0.3.x and pass an independent --texture-profile through GUI and Agent builds
• inspect portable texture source mappings and surface missing/unusable profile diagnostics
• display loop and one-shot texture layers in scene previews, with bilingual UI and updated user documentation

Validation

• cargo fmt --check, cargo clippy, and cargo test
• npm run check and npm test
• real ScoreKit 0.3 build with loop/one-shot textures and aligned stems