feat(KB-014): add spec editing and AI revision to dashboard

- Add SpecEditor component with view/edit modes and AI revision UI
- Add spec revision API endpoint with column transition validation
- Enhance TriageProcessor for re-specification with feedback support
- Integrate Spec tab in TaskDetailModal with full edit capabilities
- Add comprehensive tests for SpecEditor and revision workflows

packages/dashboard/app/api.ts

@@ -117,6 +117,13 @@ export function addSteeringComment(id: string, text: string): Promise<Task> {
   });
 }
 
+export function requestSpecRevision(id: string, feedback: string): Promise<Task> {
+  return api<Task>(`/tasks/${id}/spec/revise`, {
+    method: "POST",
+    body: JSON.stringify({ feedback }),
+  });
+}
+
 // --- Models API ---
 
 /** Available AI model info returned by the models endpoint */