feat: add cmdk dependency and enhance canvas node creation with edge splitting functionality

- Introduced the cmdk package for improved command palette capabilities.
- Enhanced the canvas placement context to support creating nodes with edge splitting, allowing for more dynamic node interactions.
- Updated the canvas inner component to utilize optimistic updates for node creation, improving user experience during interactions.
- Refactored node handling logic to incorporate new mutation types and streamline data management.

package.json

@@ -22,6 +22,7 @@
     "better-auth": "^1.5.6",
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
+    "cmdk": "^1.1.1",
     "convex": "^1.34.0",
     "framer-motion": "^12.38.0",
     "goey-toast": "^0.3.0",