feat(drums): capture velocities alongside times in unmapped-percussion reporting (#808)

* feat(drums): capture velocities alongside times in unmapped-percussion reporting

Both drum converters opt-in out_unmapped capture (convert_drum_track_from_midi,
convert_drum_track_to_drumtab) gain an index-aligned `velocities` list next to
`times`, carrying each dropped note real dynamics — MIDI velocity verbatim; GP
velocity with the same 1-127 gate as mapped hits, falling back to the 100
import default. A hand-mapping UI (the editor unmapped-notes dialog) can then
restore mapped notes at their source dynamics instead of flattening to v:100
(editor-side consumer: feedBack-plugin-editor#111).

The GP path chronological sort now reorders times and velocities in LOCKSTEP
so multi-voice measures cannot silently reassign dynamics. Additive: callers
that ignore the new key are unaffected.

Tests: extended tests/test_midi_import_drums.py + tests/test_gp2rs_drums.py
(alignment, lockstep sort, out-of-range fallback) — 26 passing.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JEoFeTPSnz4NpwwCG52hnu

* docs(gp2rs): clarify velocity-default comment, mark dead-path fallback

- The mapped-GP velocity comment conflated GP's authoring default (95,
  Velocities.default) with the drumtab render default (100,
  DEFAULT_VELOCITY in lib/drums.py) used when `v` is omitted. Clarify
  both defaults and that only the latter applies to omitted hits.
- Mark the `else: times.sort()` fallback in the unmapped-percussion
  time/velocity sort as belt-and-suspenders — times and velocities are
  always appended together under the same len<100 guard, so lengths
  can't actually diverge.

No behavior change; comment-only maintainability nits from PR review.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: ChrisBeWithYou <chris@rifflarr.local>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Co-authored-by: byrongamatos <xasiklas@gmail.com>

lib/midi_import.py

@@ -634,10 +634,12 @@ def convert_drum_track_from_midi(
 
     Callers can pass an empty dict as ``out_unmapped`` to receive a
     per-MIDI record of every channel-9 note_on that didn't resolve to a
-    piece-id (``{midi: {"count": int, "times": [float, ...]}}``, times
-    capped at 100 samples per note). The default path skips this
-    capture entirely so MIDIs heavy with cowbell/tambourine/etc. take
-    no extra work.
+    piece-id (``{midi: {"count": int, "times": [float, ...],
+    "velocities": [int, ...]}}``, times/velocities index-aligned and
+    capped at 100 samples per note — velocities carry the source notes'
+    real dynamics so a hand-mapping UI doesn't have to flatten them to a
+    default). The default path skips this capture entirely so MIDIs
+    heavy with cowbell/tambourine/etc. take no extra work.
     """
     offset = float(audio_offset)
     if not math.isfinite(offset):
@@ -675,10 +677,13 @@ def convert_drum_track_from_midi(
                     continue
                 t = tick_to_seconds(abs_tick) + offset
                 entry = out_unmapped.setdefault(
-                    midi_note, {"count": 0, "times": []})
+                    midi_note, {"count": 0, "times": [], "velocities": []})
                 entry["count"] += 1
                 if len(entry["times"]) < 100:
                     entry["times"].append(round(t, 3))
+                    # Index-aligned with times: the note's real dynamics,
+                    # so hand-mapping doesn't flatten everything to 100.
+                    entry["velocities"].append(int(msg.velocity))
                 continue
             # Mapped note: compute t once for the raw entry.
             t = tick_to_seconds(abs_tick) + offset