stub in loop operation

src/kiri/mode/cam/op-loop.js

@@ -0,0 +1,17 @@
+/** Copyright Stewart Allen <sa@grid.space> -- All Rights Reserved */
+
+import { CamOp } from './op.js';
+
+export class OpLoop extends CamOp {
+    weight() {
+        return 0;  // No weight, acts as marker
+    }
+
+    async slice() {
+        // No-op: expansion happens in slice.js
+    }
+
+    prepare() {
+        // No-op: ignored during g-code generation
+    }
+}