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;

src/utils/defaultRecipes.ts

@@ -43,6 +43,11 @@ export const FILM_SIMS: FilmSim[] = [
   { id: 'sim-astia', name: 'ASTIA', baseFilter: 'astia', adjustments: { ...DEFAULT_ADJUSTMENTS } },
   { id: 'sim-eterna', name: 'ETERNA', baseFilter: 'eterna', adjustments: { ...DEFAULT_ADJUSTMENTS } },
   { id: 'sim-acros', name: 'ACROS', baseFilter: 'monochrome', adjustments: { ...DEFAULT_ADJUSTMENTS } },
+  // Leica digital look (M/Q/SL) is NOT a film stock: neutral-but-warm colour
+  // with restrained saturation, deep open shadows and gentle highlight rolloff.
+  // Matrix-only here (like every sim) — the tonal half lives in the leica
+  // matrix (mild contrast + warm neutrality); users stack DR/tone on top.
+  { id: 'sim-leica', name: 'LEICA', baseFilter: 'leica', adjustments: { ...DEFAULT_ADJUSTMENTS } },
 ];
 
 // Film sim → full Recipe (never persisted; sims are applied on the fly).