Pen: Path Operations menu, as in Photoshop (#1397)

The Pen, Freeform Pen and Curvature Pen options bar gets Photoshop's Path
Operations button: New Layer (Shape mode), Combine Shapes, Subtract Front
Shape, Intersect Shape Areas, Exclude Overlapping Shapes and Merge Shape
Components. In Shape mode a new path is added to the selected shape layer
with the chosen operation, so a hole can be cut in a shape (#7533); in Path
mode the operation applies to the subpath added to a targeted vector mask,
the selected path or the Work Path.

- engine: path.mergeShapeComponents for work, saved and layer paths, sharing
  bake_path with the shape-layer command
- control/MCP: ui.set penMode and penPathOp
- original path-op icons, tooltip translated in every catalog

Closes #1397. Closes #7533.

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

assets/icons/path-op-combine.svg

@@ -0,0 +1,13 @@
+<svg
+  xmlns="http://www.w3.org/2000/svg"
+  width="24"
+  height="24"
+  viewBox="0 0 24 24"
+  fill="none"
+  stroke="currentColor"
+  stroke-width="2"
+  stroke-linecap="round"
+  stroke-linejoin="round"
+>
+  <path d="M3 3h12v6h6v12H9v-6H3z" fill="currentColor" />
+</svg>

assets/icons/path-op-exclude.svg

@@ -0,0 +1,13 @@
+<svg
+  xmlns="http://www.w3.org/2000/svg"
+  width="24"
+  height="24"
+  viewBox="0 0 24 24"
+  fill="none"
+  stroke="currentColor"
+  stroke-width="2"
+  stroke-linecap="round"
+  stroke-linejoin="round"
+>
+  <path d="M3 3h12v12H3zM9 9h12v12H9z" fill="currentColor" fill-rule="evenodd" />
+</svg>

assets/icons/path-op-intersect.svg

@@ -0,0 +1,15 @@
+<svg
+  xmlns="http://www.w3.org/2000/svg"
+  width="24"
+  height="24"
+  viewBox="0 0 24 24"
+  fill="none"
+  stroke="currentColor"
+  stroke-width="2"
+  stroke-linecap="round"
+  stroke-linejoin="round"
+>
+  <rect x="3" y="3" width="12" height="12" />
+  <rect x="9" y="9" width="12" height="12" />
+  <path d="M9 9h6v6H9z" fill="currentColor" />
+</svg>

assets/icons/path-op-merge.svg

@@ -0,0 +1,13 @@
+<svg
+  xmlns="http://www.w3.org/2000/svg"
+  width="24"
+  height="24"
+  viewBox="0 0 24 24"
+  fill="none"
+  stroke="currentColor"
+  stroke-width="2"
+  stroke-linecap="round"
+  stroke-linejoin="round"
+>
+  <path d="M3 3h12v6h6v12H9v-6H3z" />
+</svg>

assets/icons/path-op-new-layer.svg

@@ -0,0 +1,13 @@
+<svg
+  xmlns="http://www.w3.org/2000/svg"
+  width="24"
+  height="24"
+  viewBox="0 0 24 24"
+  fill="none"
+  stroke="currentColor"
+  stroke-width="2"
+  stroke-linecap="round"
+  stroke-linejoin="round"
+>
+  <rect x="4" y="4" width="16" height="16" rx="1" fill="currentColor" />
+</svg>

assets/icons/path-op-subtract.svg

@@ -0,0 +1,14 @@
+<svg
+  xmlns="http://www.w3.org/2000/svg"
+  width="24"
+  height="24"
+  viewBox="0 0 24 24"
+  fill="none"
+  stroke="currentColor"
+  stroke-width="2"
+  stroke-linecap="round"
+  stroke-linejoin="round"
+>
+  <path d="M3 3h12v6H9v6H3z" fill="currentColor" />
+  <rect x="9" y="9" width="12" height="12" />
+</svg>