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>

server/routers/features.py

@@ -17,6 +17,7 @@ from ..schemas import (
     FeatureCreate,
     FeatureListResponse,
     FeatureResponse,
+    FeatureUpdate,
 )
 from ..utils.validation import validate_project_name
 
@@ -217,6 +218,63 @@ async def get_feature(project_name: str, feature_id: int):
         raise HTTPException(status_code=500, detail="Database error occurred")
 
 
+@router.patch("/{feature_id}", response_model=FeatureResponse)
+async def update_feature(project_name: str, feature_id: int, update: FeatureUpdate):
+    """
+    Update a feature's details.
+
+    Only features that are not yet completed (passes=False) can be edited.
+    This allows users to provide corrections or additional instructions
+    when the agent is stuck or implementing a feature incorrectly.
+    """
+    project_name = validate_project_name(project_name)
+    project_dir = _get_project_path(project_name)
+
+    if not project_dir:
+        raise HTTPException(status_code=404, detail=f"Project '{project_name}' not found in registry")
+
+    if not project_dir.exists():
+        raise HTTPException(status_code=404, detail="Project directory not found")
+
+    _, Feature = _get_db_classes()
+
+    try:
+        with get_db_session(project_dir) as session:
+            feature = session.query(Feature).filter(Feature.id == feature_id).first()
+
+            if not feature:
+                raise HTTPException(status_code=404, detail=f"Feature {feature_id} not found")
+
+            # Prevent editing completed features
+            if feature.passes:
+                raise HTTPException(
+                    status_code=400,
+                    detail="Cannot edit a completed feature. Features marked as done are immutable."
+                )
+
+            # Apply updates for non-None fields
+            if update.category is not None:
+                feature.category = update.category
+            if update.name is not None:
+                feature.name = update.name
+            if update.description is not None:
+                feature.description = update.description
+            if update.steps is not None:
+                feature.steps = update.steps
+            if update.priority is not None:
+                feature.priority = update.priority
+
+            session.commit()
+            session.refresh(feature)
+
+            return feature_to_response(feature)
+    except HTTPException:
+        raise
+    except Exception:
+        logger.exception("Failed to update feature")
+        raise HTTPException(status_code=500, detail="Failed to update feature")
+
+
 @router.delete("/{feature_id}")
 async def delete_feature(project_name: str, feature_id: int):
     """Delete a feature."""

server/schemas.py

@@ -87,6 +87,15 @@ class FeatureCreate(FeatureBase):
     priority: int | None = None
 
 
+class FeatureUpdate(BaseModel):
+    """Request schema for updating a feature (partial updates allowed)."""
+    category: str | None = None
+    name: str | None = None
+    description: str | None = None
+    steps: list[str] | None = None
+    priority: int | None = None
+
+
 class FeatureResponse(FeatureBase):
     """Response schema for a feature."""
     id: int