fix(tools): add modifier key support for advanced brush tools

TypeScript compilation fixes:
- Added modifier keys (altKey, ctrlKey, shiftKey, metaKey) to PointerState interface
- Updated all PointerState creations in canvas to include modifier keys
- Added 'smudge' and 'dodge' cursor definitions to tool store

Tool integration:
- Added 'clone', 'smudge', 'dodge' to drawing tools array in canvas
- Clone Stamp uses Alt+Click to set source point
- Dodge/Burn uses Alt key to toggle between dodge (lighten) and burn (darken) modes
- Smudge tool benefits from modifier key tracking for future enhancements

All tools now properly receive keyboard modifier state for advanced interactions.
Build verified successful with pnpm build.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

types/canvas.ts

@@ -55,6 +55,14 @@ export interface PointerState {
   prevY: number;
   /** Pressure (0-1, for stylus) */
   pressure: number;
+  /** Alt key modifier */
+  altKey?: boolean;
+  /** Ctrl key modifier */
+  ctrlKey?: boolean;
+  /** Shift key modifier */
+  shiftKey?: boolean;
+  /** Meta key modifier */
+  metaKey?: boolean;
 }
 
 /**