Skill audit report

mc-arrangement-arch Audit report.

Arrangement architecture (编曲结构学) - the shape of a track over time rather than its notes. Energy curve and dramatic arc, subtractive arranging, layering as form (instrument entry/exit events), formal skeletons and section proportion, arrangement-hook placement, why the second verse must not be a copy, and how to end. Use when the user is arranging a song and asks how to structure it, when a track "goes nowhere" or "sounds flat", when every section sounds the same, when a generated track sounds like AI (monotonic energy, unchanging instrumentation, no subtraction), when deciding where instruments enter and leave, or when filling the arrangement/energy_curve/subtraction_events/roster fields of an ARR-SPEC. 编曲结构、能量曲线、减法、进退场、段落比例、钩子布局、结尾。