Add keyboard handling for deleting adjacent metric nodes

Co-authored-by: natemkelley <natemkelley@gmail.com>

apps/web/src/components/ui/report/plugins/metric-kit/metric-kit.tsx

@@ -34,6 +34,54 @@ export const MetricPlugin = createPlatePlugin<
     isElement: true,
     isVoid: false,
     component: MetricElement
+  },
+  handlers: {
+    onKeyDown: ({ editor, event }) => {
+      // Only handle single-caret (collapsed) cases
+      if (!editor.api.isCollapsed()) return true;
+
+      const key = event.key;
+      if (key !== 'Backspace' && key !== 'Delete') return true;
+
+      const block = editor.api.block<TElement>();
+      if (!block) return true;
+
+      const [, path] = block;
+
+      // Helper to get sibling at offset from current block index
+      const getSiblingEntry = (offset: number) => {
+        const index = path[path.length - 1] + offset;
+        if (index < 0) return undefined;
+        const siblingPath = [...path.slice(0, -1), index] as unknown as Path;
+        return editor.api.node<TElement>(siblingPath);
+      };
+
+      // Backspace at start of block should remove previous metric node
+      if (key === 'Backspace' && editor.api.isAt({ start: true })) {
+        const prevEntry = getSiblingEntry(-1);
+        if (!prevEntry) return true;
+        const [prevNode, prevPath] = prevEntry;
+        if ((prevNode as TElement).type === CUSTOM_KEYS.metric) {
+          event.preventDefault();
+          editor.tf.removeNodes({ at: prevPath });
+          return false;
+        }
+      }
+
+      // Delete at end of block should remove next metric node
+      if (key === 'Delete' && editor.api.isAt({ end: true })) {
+        const nextEntry = getSiblingEntry(1);
+        if (!nextEntry) return true;
+        const [nextNode, nextPath] = nextEntry;
+        if ((nextNode as TElement).type === CUSTOM_KEYS.metric) {
+          event.preventDefault();
+          editor.tf.removeNodes({ at: nextPath });
+          return false;
+        }
+      }
+
+      return true;
+    }
   }
 }).extendApi(({ setOption, plugin, editor, tf, ...rest }) => {
   return {