fix: sidechain CC11 — pass kick_cache to build_bass_track + absolute position projection

Root cause: build_bass_track() never received the kick_cache in main().
Second issue: kick times were WAV-relative (0-12 beats) but bass expects
absolute positions (16+ beats). Added loop-duration projection to convert
relative → absolute positions across clip duration.

285 CC11 events now generated in output. 302/302 tests pass.

scripts/compose.py

@@ -265,6 +265,7 @@ def build_section_structure():
 # ---------------------------------------------------------------------------
 
 _kick_cache: dict[str, list[float]] = {}
+_LOOP_DURATIONS: dict[str, float] = {}
 _KICK_CONFIDENCE_THRESHOLD = 0.6
 
 _CC11_DIP = 50
@@ -293,6 +294,7 @@ def _get_kick_cache(drumloop_paths: list[str], bpm: float) -> dict[str, list[flo
             ]
             beat_dur = 60.0 / bpm
             _kick_cache[path] = [t.time / beat_dur for t in kicks]
+            _LOOP_DURATIONS[path] = analysis.duration / beat_dur
         except Exception:
             _kick_cache[path] = []
 
@@ -758,12 +760,40 @@ def main() -> None:
     drumloop_paths = sorted({c.audio_path for c in drumloop_track.clips if c.audio_path})
     if drumloop_paths:
         _get_kick_cache(drumloop_paths, bpm)
+        for path, kicks in _kick_cache.items():
+            print(f"  Kick cache: {len(kicks)} kicks in {Path(path).name}")
+
+        # Project relative kicks to absolute timeline positions per clip
+        _abs_kicks: dict[str, list[float]] = {}
+        for clip in drumloop_track.clips:
+            path = clip.audio_path
+            if not path or path not in _kick_cache:
+                continue
+            rel_kicks = _kick_cache[path]
+            if not rel_kicks:
+                continue
+            loop_beats = _LOOP_DURATIONS.get(path, 8.0)
+            abs_positions: list[float] = []
+            loop_n = 0
+            while loop_n * loop_beats < clip.length:
+                offset = clip.position + loop_n * loop_beats
+                for k in rel_kicks:
+                    abs_pos = offset + k
+                    if abs_pos < clip.position + clip.length:
+                        abs_positions.append(abs_pos)
+                loop_n += 1
+            if path in _abs_kicks:
+                _abs_kicks[path].extend(abs_positions)
+            else:
+                _abs_kicks[path] = abs_positions
+        _kick_cache.clear()
+        _kick_cache.update(_abs_kicks)
 
     # Build tracks
     tracks = [
         build_drumloop_track(sections, offsets, seed=args.seed or 0),
         build_perc_track(sections, offsets, seed=args.seed or 0),
-        build_bass_track(sections, offsets, key_root, key_minor),
+        build_bass_track(sections, offsets, key_root, key_minor, kick_cache=_kick_cache),
         build_chords_track(sections, offsets, key_root, key_minor,
                            emotion=args.emotion, inversion=args.inversion),
         build_lead_track(sections, offsets, key_root, key_minor, seed=args.seed or 42),