Add Cursor error type

src/lib/painter/errors.ts

@@ -0,0 +1,12 @@
+export class PaintCursorError extends Error {
+  cursorX
+  cursorY
+
+  constructor(message: string, {x, y}: {x: unknown, y: unknown}) {
+    super(message)
+
+    this.name = this.constructor.name
+    this.cursorX = !x ? 'No data' : x
+    this.cursorY = !y ? 'No data' : y
+  }
+}