CAM routing refactor, area operation, and taper ball tool implementation

Major routing improvements:
- Refactor depth-first routing algorithm for better path optimization
- Reimplemented outline, roughing, pocket, and trace as area operation wrappers
- Add pocket shadow travel routing with optimized descent using travel bounds
- Improve contour routing with arc detection and polyEmit arc strategy
- Add area smoothing and ease-down options
- Fix outline handling with thru holes and surface reversal on tip2tip
- Move widget shadow methods into widget class for faster hole detection
- Better camInnerFirst support and proper feed/plunge defaults

Tool system improvements:
- Implement taper ball tool type with full support
- Add renderTool2() for profile-based visualization
- Convert tool menu to init code with bound vars
- Fix auto tool and auto spindle for prep operations
- Update tool profile generation for taperball geometry
- Add calcTaperBallExtent() for proper ball tangency calculations

Code cleanup:
- Remove duplicated slicer code from specialized slicers
- Asyncify shadowAt operations
- Deprecate pocket engrave operation
- Simplify upNover implementation
- Fix animation with new tool+settings requirements

src/kiri/core/consts.js

@@ -130,6 +130,18 @@ const LISTS = {
     surftyp: [
         { name: "linear" },
         { name: "offset" },
+    ],
+    direction: [
+        { name: "climb" },
+        { name: "conventional" },
+        { name: "alternating" },
+    ],
+    camtool: [
+        { name: "flat end",   id: "endmill" },
+        { name: "ball end",   id: "ballmill" },
+        { name: "taper tip",  id: "tapermill" },
+        { name: "taper ball", id: "taperball" },
+        { name: "drill bit",  id: "drill" },
     ]
 };