Bake window: derived note lengths carry exact durations, not ladder rungs — a long take is no longer cut at 384 beats

Hold keeps its picker. Also: one home for the %-fold, duration-ordered Hold travel, and a corrupt tail degrades to absent rather than fabricating one.

src/core/instrument/engine/play_params.h

@@ -195,13 +195,29 @@ bool splineActive(const Play& p) {
            (p.filter.enabled && p.filterSpline.mode == EnvMode::Spline);
 }
 
-// The one enforcement of splineActive's rule (see its doc above). Header-inline and
-// allocation-free: play_params.h sits on the per-voice-per-sample include path. Both callers —
-// resolvePlay (sample_map.cpp) and the editor's applyControl — route through here, so the two
-// cannot drift apart.
+// The mode the engine will actually run, and the one home of splineActive's rule (see its doc
+// above). Header-inline and allocation-free: play_params.h sits on the per-voice-per-sample
+// include path. Every caller — resolvePlay (sample_map.cpp), the editor's applyControl, and
+// the editor's read-only predicates — routes through one of these two, so none of them can
+// drift into a second reading of the fields.
+template <class Play>
+PlayMode effectivePlayMode(const Play& p) {
+    return splineActive(p) ? PlayMode::Trigger : p.playMode;
+}
+
 template <class Play>
 void enforceGateUnavailableWhileDrawn(Play& p) {
-    if (splineActive(p)) p.playMode = PlayMode::Trigger;
+    p.playMode = effectivePlayMode(p);
+}
+
+// The %-length the voice ACTUALLY plays. Same rule family, same reason it is templated: a drawn
+// contour is a pure time function over the full sample length, so any active spline EG folds
+// the fraction to 1.0 while the stored knob goes inert — but the stored value survives, so a
+// pre-spline setting is still there to be read. Every consumer of the Trigger span must fold it
+// here or it silently plays/draws/bakes a fraction of the take.
+template <class Play>
+double effectiveLengthFraction(const Play& p) {
+    return splineActive(p) ? 1.0 : p.trigger.lengthFraction;
 }
 
 // [start, end) frames, half-open. A zero-length loop (start == end) is the "no sustain loop"