Retire the zone system: one capture = one parameter set, and re-seam the engine and Sample face into bands

src/core/instrument/ui/sample_chrome.h

@@ -0,0 +1,34 @@
+#pragma once
+// sample_chrome.h — interior geometry of the Sample face's CHROME band: the toolbar row
+// (title + Browse) over the control row (root/piano strip, preview trigger, preview-velocity
+// knob cell, curve-preview button, Mono|Stereo toggle). Reads the band rect the allocator
+// hands it (sample_bands) and never allocates vertical space of its own.
+
+#include "core/instrument/ui/editor_geometry.h"  // Rect
+
+namespace reasampler::instrument::ui {
+
+inline constexpr int kNavButtonWidth = 62;  // the Browse toolbar button
+
+// Every interactive rect inside the chrome band, in one pass so draw and hit-test cannot
+// derive them differently. The control row's right-anchored run is fixed-width (preview,
+// velocity cell, curve button, channel toggle) and the root strip takes the remainder, so
+// the strip grows with the window.
+struct ChromeRects {
+    Rect toolbar;     // full-width top row
+    Rect navBrowse;   // right-anchored in the toolbar
+    Rect controls;    // full-width second row
+    Rect rootStrip;   // remainder-width, left
+    Rect preview;
+    Rect velCell;     // preview-velocity knob cell (knob + label band)
+    Rect velKnob;
+    Rect velLabel;
+    Rect curveBtn;    // opens the velocity-curve popup
+    Rect chanMono;
+    Rect chanStereo;
+};
+
+// `knobSize` is the deck knob square, passed in so this module does not depend on knob_deck.
+ChromeRects chromeRects(const Rect& chrome, int knobSize);
+
+}  // namespace reasampler::instrument::ui