M4.2: optics — manual distortion/vignetting, lateral CA (auto + manual), defringe, DNG-embedded profile corrections

- pipeline::optics::Warp: one inverse map (lens-corrected → source) inside the single geometry resample:
  manual radial distortion, embedded DNG WarpRectilinear (per plane), per-channel lateral CA scale,
  radial vignetting gain (manual + embedded FixVignetteRadial); all in normalized radii
- automatic lateral CA estimate: radial edge profiles matched sub-pixel per plane, robust LSQ fit of
  displacement = α·r (cached per source)
- defringe: purple/green hue ranges (OkLab hue) desaturated next to high-contrast edges, width relative
  to the image long edge
- "Enable Lens Corrections" applies only lens data embedded in DNGs (opcodes are no longer baked at decode;
  stored on the photo record, on by default at import when present). No LCP data anywhere.
- new controls: optics.caRed/caBlue, defringe hue ranges; Optics panel: Manual sub-section, Defringe flyout
- tests: barrel grid straightened, CA removal (auto + manual), embedded corrections toggle/scale, preview vs
  export resolution independence, CA estimator accuracy, orientation of embedded lens data

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/develop/src/controls.rs

@@ -213,7 +213,13 @@ controls! {
     "optics.profileDistortion" => optics.profile_distortion, "Profile Distortion", Optics, 0, 200, 100, 1, 0, Plain;
     "optics.profileVignetting" => optics.profile_vignetting, "Profile Vignetting", Optics, 0, 200, 100, 1, 0, Plain;
     "optics.defringePurple" => optics.defringe_purple_amount, "Purple Amount", Optics, 0, 20, 0, 1, 0, Gradient { from: "#7a7a7a", to: "#a040d0" };
+    "optics.defringePurpleHueLo" => optics.defringe_purple_hue_lo, "Purple Hue Low", Optics, 0, 90, 30, 1, 0, Gradient { from: "#6040e0", to: "#d040b0" };
+    "optics.defringePurpleHueHi" => optics.defringe_purple_hue_hi, "Purple Hue High", Optics, 10, 100, 70, 1, 0, Gradient { from: "#6040e0", to: "#d040b0" };
     "optics.defringeGreen" => optics.defringe_green_amount, "Green Amount", Optics, 0, 20, 0, 1, 0, Gradient { from: "#7a7a7a", to: "#40c040" };
+    "optics.defringeGreenHueLo" => optics.defringe_green_hue_lo, "Green Hue Low", Optics, 0, 90, 40, 1, 0, Gradient { from: "#c0d030", to: "#30c0b0" };
+    "optics.defringeGreenHueHi" => optics.defringe_green_hue_hi, "Green Hue High", Optics, 10, 100, 60, 1, 0, Gradient { from: "#c0d030", to: "#30c0b0" };
+    "optics.caRed" => optics.ca_red, "Red/Cyan Fringe", Optics, -100, 100, 0, 1, 0, Gradient { from: "#30c0c0", to: "#e04040" };
+    "optics.caBlue" => optics.ca_blue, "Blue/Yellow Fringe", Optics, -100, 100, 0, 1, 0, Gradient { from: "#d0c030", to: "#4060e0" };
     "geometry.vertical" => geometry.vertical, "Vertical", Geometry, -100, 100, 0, 1, 0, Centered;
     "geometry.horizontal" => geometry.horizontal, "Horizontal", Geometry, -100, 100, 0, 1, 0, Centered;
     "geometry.rotate" => geometry.rotate, "Rotate", Geometry, -10, 10, 0, 0.1, 1, Centered;

crates/develop/src/settings.rs

@@ -419,6 +419,10 @@ pub struct Optics {
     pub distortion: f64,
     pub vignetting: f64,
     pub vignetting_midpoint: f64,
+    /// Manual lateral chromatic aberration (red/cyan, blue/yellow fringes), −100..100, added to the
+    /// automatic estimate when `remove_ca` is on.
+    pub ca_red: f64,
+    pub ca_blue: f64,
 }
 
 impl Default for Optics {
@@ -437,10 +441,42 @@ impl Default for Optics {
             distortion: 0.0,
             vignetting: 0.0,
             vignetting_midpoint: 50.0,
+            ca_red: 0.0,
+            ca_blue: 0.0,
         }
     }
 }
 
+/// Lens corrections embedded in a DNG file (`OpcodeList3`: `WarpRectilinear`, `FixVignetteRadial`), converted
+/// to the oriented, default-cropped image. This is camera/file data (stored on the photo record, not in the develop
+/// settings); "Enable Profile Corrections" applies it, scaled by the profile distortion/vignetting amounts.
+/// LightCraft never uses Adobe LCP lens profiles.
+#[derive(Clone, Copy, Debug, Default, PartialEq, Serialize, Deserialize)]
+#[serde(default)]
+pub struct EmbeddedLens {
+    pub warp: Option<EmbeddedWarp>,
+    pub vignette: Option<EmbeddedVignette>,
+}
+
+/// DNG `WarpRectilinear`: per plane (R, G, B) `[kr0, kr1, kr2, kr3, kt0, kt1]`. For an output (corrected) point at
+/// offset `d = (p − center) / radius`, the source point is `center + radius · (d·f(r²) + tangential(d))`.
+#[derive(Clone, Copy, Debug, Default, PartialEq, Serialize, Deserialize)]
+pub struct EmbeddedWarp {
+    pub planes: [[f64; 6]; 3],
+    /// Optical centre, normalized to the oriented image (0..1).
+    pub center: Point,
+    /// Normalisation radius as a fraction of the oriented image's long edge.
+    pub radius: f64,
+}
+
+/// DNG `FixVignetteRadial`: gain `1 + k0 r² + k1 r⁴ + … + k4 r¹⁰` with `r = |p − center| / radius`.
+#[derive(Clone, Copy, Debug, Default, PartialEq, Serialize, Deserialize)]
+pub struct EmbeddedVignette {
+    pub k: [f64; 5],
+    pub center: Point,
+    pub radius: f64,
+}
+
 #[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub enum Upright {