feat(skills): add inspect-elements skill backed by element-source

Closes #1082

src/lib/react-scan.ts

@@ -4,6 +4,75 @@ if (import.meta.env.DEV) {
       enabled: true,
       showToolbar: !(window as any).__PROFILING__,
     });
+
+    const notReady = async () => ({
+      error: 'element-source is not ready yet.',
+    });
+
+    const elementSourceApi: any = {
+      ready: false,
+      error: null,
+      resolve: notReady,
+      resolveBySelector: async () => ({
+        error: 'element-source is not ready yet.',
+      }),
+      resolveAtPoint: async () => ({
+        error: 'element-source is not ready yet.',
+      }),
+      formatStack: () => '',
+    };
+
     (window as any).__getReactScanReport = getReport;
+    (window as any).__ELEMENT_SOURCE__ = elementSourceApi;
+
+    import('element-source')
+      .then(({ formatStack, resolveElementInfo }) => {
+        const resolve = async (node: unknown) => {
+          if (!(node instanceof Element)) {
+            return {
+              error: 'Expected a DOM Element.',
+            };
+          }
+
+          try {
+            const info = await resolveElementInfo(node);
+            return {
+              ...info,
+              available: Boolean(info.source || info.stack.length || info.componentName),
+            };
+          } catch (error) {
+            return {
+              error: error instanceof Error ? error.message : String(error),
+            };
+          }
+        };
+
+        Object.assign(elementSourceApi, {
+          ready: true,
+          resolve,
+          resolveBySelector: async (selector: string) => {
+            const element = document.querySelector(selector);
+            if (!(element instanceof Element)) {
+              return {
+                error: `No element matched selector: ${selector}`,
+              };
+            }
+            return resolve(element);
+          },
+          resolveAtPoint: async (x: number, y: number) => {
+            const element = document.elementFromPoint(x, y);
+            if (!(element instanceof Element)) {
+              return {
+                error: `No element found at point (${x}, ${y})`,
+              };
+            }
+            return resolve(element);
+          },
+          formatStack: (stack: unknown, maxLines = 3) => (Array.isArray(stack) ? formatStack(stack as any, maxLines) : ''),
+        });
+      })
+      .catch((error) => {
+        elementSourceApi.error = error instanceof Error ? error.message : String(error);
+      });
   });
 }