The coarse-path fallback now expands each 10 Hz step to five 50 Hz steps so its
diagonals still yield bar anchors; fine band widths are injectable to test it.
Offset pooling is clipped to the current segment, and auto anchors need
audioSec > 0 unless midiSec is 0. Tests: forced fallback, wrong manual anchor,
p90 bound; debug output gated behind ALIGN_DEBUG.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
Coarse (10 Hz) DTW per stretch between manual anchors, refined at 50 Hz in a
band that widens 0.5 -> 1 -> 2 s on unreachable end cells (coarse path as last
resort); one auto anchor per bar from median offsets of diagonal path steps.
Fit quality from raw-audio onset peaks vs warped scored-role MIDI onsets
(+-70 ms, 30 s windows, flagged on rate < 0.5 or median > 60 ms).
trackKeys moves to src/align/roles.ts (pure) and is re-exported by manifest.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
