v0.8.7: Add 1SHOT mode, move STRETCH to row 1, fix MIDI All Notes Off/Sound Off

- Add per-slice and sample-level one-shot mode (1SHOT): voice plays to end
  of slice regardless of note-off; lockable per slice
- Move STRETCH toggle from row 2 to row 1 in both HeaderBar and SliceControlBar
  (sits after algo-specific params alongside ALGO conceptually)
- Rename 1SHT label to 1SHOT; add 1SHOT to HeaderBar row 1
- Normalise STRETCH ON colour to lockActive (orange) — consistent with all
  other boolean toggles (TAIL, REV, FMNT C, 1SHOT)
- Handle MIDI All Notes Off (CC 123) and All Sound Off (CC 120): new
  VoicePool::releaseAll() releases all active voices including one-shot;
  graceful on CC 123, immediate 5ms fade on CC 120

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: tucktuckg00se

src/ui/HeaderBar.cpp

@@ -217,7 +217,7 @@ void HeaderBar::paint (juce::Graphics& g)
             g.setColour (getTheme().foreground.withAlpha (0.9f));
             g.drawText ("STRETCH", x, row1y + 2, cellW, 13, juce::Justification::centredLeft);
             g.setFont (IntersectLookAndFeel::makeFont (14.0f));
-            g.setColour (strOnR1 ? getTheme().accent : getTheme().foreground.withAlpha (0.5f));
+            g.setColour (strOnR1 ? getTheme().lockActive : getTheme().foreground.withAlpha (0.5f));
             g.drawText (strOnR1 ? "ON" : "OFF", x, row1y + 15, cellW, 14, juce::Justification::centredLeft);
             headerCells.push_back ({ x, row1y, cellW, row1h, ParamIds::defaultStretchEnabled, 0.0f, 1.0f, 1.0f, false, true, false, false });
             x += cellW + cellGap;