feat(presets): add LEICA simulation chip; collapse recipe strip on sim select

src/utils/colorUtils.ts

@@ -98,6 +98,22 @@ export function getSkiaColorMatrix(baseFilter: BaseFilter, adj: ColorAdjustments
       0.02, 0.02, 0.94, 0, 0.02,
       0, 0, 0, 1, 0,
     ];
+  } else if (baseFilter === 'leica') {
+    // Leica digital look (M/Q/SL): neutral-but-warm, deep yet open shadows,
+    // restrained saturation with deep reds and true greens — never the punchy
+    // chroma of Velvia or the amber of Classic Neg. A linear matrix cannot do
+    // the smooth highlight rolloff (that's the tone shader's job), so this only
+    // carries the mild contrast/warmth/colour balance half:
+    //   - gentle contrast around mid-grey (deep blacks, no lifted blacks)
+    //   - slight warm cast in highlights (R up, B down), near-neutral white
+    //   - reds a touch deeper, blues slightly muted towards natural skies
+    //   - green mostly untouched (Leica greens stay true, not olive)
+    matrix = [
+      1.08, -0.02, -0.01, 0, -0.025,
+      -0.015, 1.06, -0.01, 0, -0.017,
+      -0.02, -0.015, 1.04, 0, -0.013,
+      0, 0, 0, 1, 0,
+    ];
   } else if (baseFilter === 'monochrome') {
     // Acros Monochrome: ITU-R BT.709 luma — pure grayscale, zero color leakage
     const r = 0.2126;