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/mode/cam/op-index.js

@@ -25,12 +25,12 @@ export class OpIndex extends CamOp {
     }
 
     prepare(ops, progress) {
-        const { zmax, zsafe, camOut } = ops;
+        let { zmax, zsafe, camOut, printPoint } = ops;
         // max point of stock corner radius when rotating (safe z when indexing)
-        const ztop = Math.max(zsafe, zmax);
+        let ztop = Math.max(zsafe, zmax);
         // move above rotating stock
-        camOut(last = last.clone().setZ(ztop), 0);
+        camOut(printPoint = printPoint.clone().setZ(ztop), 0);
         // issue rotation command
-        camOut(last = last.clone().setZ(ztop).setA(this.degrees), 0);
+        camOut(printPoint = printPoint.clone().setZ(ztop).setA(this.degrees), 0);
     }
 }