M3.50: Overprint Black dialog with fill/stroke, rich and spot black options

Edit > Edit Colors > Overprint Black... opens a parameter dialog (Remove,
Percentage, Fill, Stroke, Include Blacks with CMY, Include Spot Blacks).
edit.colors.overprintBlack takes fill?, stroke?, includeCmyBlacks? and
includeSpotBlacks?; it covers type characters and gradients whose every stop
is black, and records no undo step when nothing changes.

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

crates/engine/src/cmd/colormgmt.rs

@@ -111,7 +111,7 @@ pub fn specs() -> Vec<CommandSpec> {
             "Overprint Black…",
             ["Edit", "Edit Colors"],
             None,
-            "{remove?: false, percentage?: 100, ids?} make the black fills and strokes (black-only ink ≥ percentage) of the selection (or ids; groups: their contents) overprint, or stop (remove) → {changed: objects}",
+            "{remove?: false, percentage?: 100, fill?: true, stroke?: true, includeCmyBlacks?: false, includeSpotBlacks?: false, ids?} make the black fills and/or strokes of the selection (or ids; groups: their contents; type: its characters) overprint, or stop (remove). Black: K ≥ percentage with no C, M or Y (any with includeCmyBlacks), not linked to a spot swatch (unless includeSpotBlacks); a gradient is black when every stop is → {changed: objects}",
             has_doc,
             super::overprint::overprint_black
         ),

crates/engine/src/cmd/overprint.rs

@@ -189,7 +189,10 @@ pub(crate) fn overprint_black(s: &mut Session, p: &Value) -> Result<Value> {
     let op = OverprintBlack {
         remove: bool_or(p, "remove", false),
         min_k: (f64_or(p, "percentage", 100.0) / 100.0).clamp(0.0, 1.0) as f32,
-        ..Default::default()
+        fill: bool_or(p, "fill", true),
+        stroke: bool_or(p, "stroke", true),
+        rich: bool_or(p, "includeCmyBlacks", false),
+        spot: bool_or(p, "includeSpotBlacks", false),
     };
     let ids = match ids_param(p, "ids") {
         Some(v) => v,