feat: add feature editing capability for pending/in-progress features

Add the ability for users to edit features that are not yet completed,
allowing them to provide corrections or additional instructions when the
agent is stuck or implementing a feature incorrectly.

Backend changes:
- Add FeatureUpdate schema in server/schemas.py with optional fields
- Add PATCH /api/projects/{project_name}/features/{feature_id} endpoint
- Validate that completed features (passes=True) cannot be edited

Frontend changes:
- Add FeatureUpdate type in ui/src/lib/types.ts
- Add updateFeature() API function in ui/src/lib/api.ts
- Add useUpdateFeature() React Query mutation hook
- Create EditFeatureForm.tsx component with pre-filled form values
- Update FeatureModal.tsx with Edit button for non-completed features

The edit form allows modifying category, name, description, priority,
and test steps. Save button is disabled until changes are detected.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

ui/src/lib/api.ts

@@ -9,6 +9,7 @@ import type {
   FeatureListResponse,
   Feature,
   FeatureCreate,
+  FeatureUpdate,
   FeatureBulkCreate,
   FeatureBulkCreateResponse,
   AgentStatusResponse,
@@ -119,6 +120,17 @@ export async function skipFeature(projectName: string, featureId: number): Promi
   })
 }
 
+export async function updateFeature(
+  projectName: string,
+  featureId: number,
+  update: FeatureUpdate
+): Promise<Feature> {
+  return fetchJSON(`/projects/${encodeURIComponent(projectName)}/features/${featureId}`, {
+    method: 'PATCH',
+    body: JSON.stringify(update),
+  })
+}
+
 export async function createFeaturesBulk(
   projectName: string,
   bulk: FeatureBulkCreate

ui/src/lib/types.ts

@@ -82,6 +82,14 @@ export interface FeatureCreate {
   priority?: number
 }
 
+export interface FeatureUpdate {
+  category?: string
+  name?: string
+  description?: string
+  steps?: string[]
+  priority?: number
+}
+
 // Agent types
 export type AgentStatus = 'stopped' | 'running' | 'paused' | 'crashed'