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/components/EditFeatureForm.tsx

@@ -0,0 +1,248 @@
+import { useState, useId } from 'react'
+import { X, Save, Plus, Trash2, Loader2, AlertCircle } from 'lucide-react'
+import { useUpdateFeature } from '../hooks/useProjects'
+import type { Feature } from '../lib/types'
+
+interface Step {
+  id: string
+  value: string
+}
+
+interface EditFeatureFormProps {
+  feature: Feature
+  projectName: string
+  onClose: () => void
+  onSaved: () => void
+}
+
+export function EditFeatureForm({ feature, projectName, onClose, onSaved }: EditFeatureFormProps) {
+  const formId = useId()
+  const [category, setCategory] = useState(feature.category)
+  const [name, setName] = useState(feature.name)
+  const [description, setDescription] = useState(feature.description)
+  const [priority, setPriority] = useState(String(feature.priority))
+  const [steps, setSteps] = useState<Step[]>(() =>
+    feature.steps.length > 0
+      ? feature.steps.map((step, i) => ({ id: `${formId}-step-${i}`, value: step }))
+      : [{ id: `${formId}-step-0`, value: '' }]
+  )
+  const [error, setError] = useState<string | null>(null)
+  const [stepCounter, setStepCounter] = useState(feature.steps.length || 1)
+
+  const updateFeature = useUpdateFeature(projectName)
+
+  const handleAddStep = () => {
+    setSteps([...steps, { id: `${formId}-step-${stepCounter}`, value: '' }])
+    setStepCounter(stepCounter + 1)
+  }
+
+  const handleRemoveStep = (id: string) => {
+    setSteps(steps.filter(step => step.id !== id))
+  }
+
+  const handleStepChange = (id: string, value: string) => {
+    setSteps(steps.map(step =>
+      step.id === id ? { ...step, value } : step
+    ))
+  }
+
+  const handleSubmit = async (e: React.FormEvent) => {
+    e.preventDefault()
+    setError(null)
+
+    const filteredSteps = steps
+      .map(s => s.value.trim())
+      .filter(s => s.length > 0)
+
+    try {
+      await updateFeature.mutateAsync({
+        featureId: feature.id,
+        update: {
+          category: category.trim(),
+          name: name.trim(),
+          description: description.trim(),
+          steps: filteredSteps,
+          priority: parseInt(priority, 10),
+        },
+      })
+      onSaved()
+    } catch (err) {
+      setError(err instanceof Error ? err.message : 'Failed to update feature')
+    }
+  }
+
+  const isValid = category.trim() && name.trim() && description.trim()
+
+  // Check if any changes were made
+  const currentSteps = steps.map(s => s.value.trim()).filter(s => s)
+  const hasChanges =
+    category.trim() !== feature.category ||
+    name.trim() !== feature.name ||
+    description.trim() !== feature.description ||
+    parseInt(priority, 10) !== feature.priority ||
+    JSON.stringify(currentSteps) !== JSON.stringify(feature.steps)
+
+  return (
+    <div className="neo-modal-backdrop" onClick={onClose}>
+      <div
+        className="neo-modal w-full max-w-2xl"
+        onClick={(e) => e.stopPropagation()}
+      >
+        {/* Header */}
+        <div className="flex items-center justify-between p-6 border-b-3 border-[var(--color-neo-border)]">
+          <h2 className="font-display text-2xl font-bold">
+            Edit Feature
+          </h2>
+          <button
+            onClick={onClose}
+            className="neo-btn neo-btn-ghost p-2"
+          >
+            <X size={24} />
+          </button>
+        </div>
+
+        {/* Form */}
+        <form onSubmit={handleSubmit} className="p-6 space-y-4">
+          {/* Error Message */}
+          {error && (
+            <div className="flex items-center gap-3 p-4 bg-[var(--color-neo-danger)] text-white border-3 border-[var(--color-neo-border)]">
+              <AlertCircle size={20} />
+              <span>{error}</span>
+              <button
+                type="button"
+                onClick={() => setError(null)}
+                className="ml-auto"
+              >
+                <X size={16} />
+              </button>
+            </div>
+          )}
+
+          {/* Category & Priority Row */}
+          <div className="flex gap-4">
+            <div className="flex-1">
+              <label className="block font-display font-bold mb-2 uppercase text-sm">
+                Category
+              </label>
+              <input
+                type="text"
+                value={category}
+                onChange={(e) => setCategory(e.target.value)}
+                placeholder="e.g., Authentication, UI, API"
+                className="neo-input"
+                required
+              />
+            </div>
+            <div className="w-32">
+              <label className="block font-display font-bold mb-2 uppercase text-sm">
+                Priority
+              </label>
+              <input
+                type="number"
+                value={priority}
+                onChange={(e) => setPriority(e.target.value)}
+                min="1"
+                className="neo-input"
+                required
+              />
+            </div>
+          </div>
+
+          {/* Name */}
+          <div>
+            <label className="block font-display font-bold mb-2 uppercase text-sm">
+              Feature Name
+            </label>
+            <input
+              type="text"
+              value={name}
+              onChange={(e) => setName(e.target.value)}
+              placeholder="e.g., User login form"
+              className="neo-input"
+              required
+            />
+          </div>
+
+          {/* Description */}
+          <div>
+            <label className="block font-display font-bold mb-2 uppercase text-sm">
+              Description
+            </label>
+            <textarea
+              value={description}
+              onChange={(e) => setDescription(e.target.value)}
+              placeholder="Describe what this feature should do..."
+              className="neo-input min-h-[100px] resize-y"
+              required
+            />
+          </div>
+
+          {/* Steps */}
+          <div>
+            <label className="block font-display font-bold mb-2 uppercase text-sm">
+              Test Steps
+            </label>
+            <div className="space-y-2">
+              {steps.map((step, index) => (
+                <div key={step.id} className="flex gap-2">
+                  <span className="neo-input w-12 text-center flex-shrink-0 flex items-center justify-center">
+                    {index + 1}
+                  </span>
+                  <input
+                    type="text"
+                    value={step.value}
+                    onChange={(e) => handleStepChange(step.id, e.target.value)}
+                    placeholder="Describe this step..."
+                    className="neo-input flex-1"
+                  />
+                  {steps.length > 1 && (
+                    <button
+                      type="button"
+                      onClick={() => handleRemoveStep(step.id)}
+                      className="neo-btn neo-btn-ghost p-2"
+                    >
+                      <Trash2 size={18} />
+                    </button>
+                  )}
+                </div>
+              ))}
+            </div>
+            <button
+              type="button"
+              onClick={handleAddStep}
+              className="neo-btn neo-btn-ghost mt-2 text-sm"
+            >
+              <Plus size={16} />
+              Add Step
+            </button>
+          </div>
+
+          {/* Actions */}
+          <div className="flex gap-3 pt-4 border-t-3 border-[var(--color-neo-border)]">
+            <button
+              type="submit"
+              disabled={!isValid || !hasChanges || updateFeature.isPending}
+              className="neo-btn neo-btn-success flex-1"
+            >
+              {updateFeature.isPending ? (
+                <Loader2 size={18} className="animate-spin" />
+              ) : (
+                <>
+                  <Save size={18} />
+                  Save Changes
+                </>
+              )}
+            </button>
+            <button
+              type="button"
+              onClick={onClose}
+              className="neo-btn neo-btn-ghost"
+            >
+              Cancel
+            </button>
+          </div>
+        </form>
+      </div>
+    </div>
+  )
+}

ui/src/components/FeatureModal.tsx

@@ -1,6 +1,7 @@
 import { useState } from 'react'
-import { X, CheckCircle2, Circle, SkipForward, Trash2, Loader2, AlertCircle } from 'lucide-react'
+import { X, CheckCircle2, Circle, SkipForward, Trash2, Loader2, AlertCircle, Pencil } from 'lucide-react'
 import { useSkipFeature, useDeleteFeature } from '../hooks/useProjects'
+import { EditFeatureForm } from './EditFeatureForm'
 import type { Feature } from '../lib/types'
 
 interface FeatureModalProps {
@@ -12,6 +13,7 @@ interface FeatureModalProps {
 export function FeatureModal({ feature, projectName, onClose }: FeatureModalProps) {
   const [error, setError] = useState<string | null>(null)
   const [showDeleteConfirm, setShowDeleteConfirm] = useState(false)
+  const [showEdit, setShowEdit] = useState(false)
 
   const skipFeature = useSkipFeature(projectName)
   const deleteFeature = useDeleteFeature(projectName)
@@ -36,6 +38,18 @@ export function FeatureModal({ feature, projectName, onClose }: FeatureModalProp
     }
   }
 
+  // Show edit form when in edit mode
+  if (showEdit) {
+    return (
+      <EditFeatureForm
+        feature={feature}
+        projectName={projectName}
+        onClose={() => setShowEdit(false)}
+        onSaved={onClose}
+      />
+    )
+  }
+
   return (
     <div className="neo-modal-backdrop" onClick={onClose}>
       <div
@@ -159,6 +173,14 @@ export function FeatureModal({ feature, projectName, onClose }: FeatureModalProp
               </div>
             ) : (
               <div className="flex gap-3">
+                <button
+                  onClick={() => setShowEdit(true)}
+                  disabled={skipFeature.isPending}
+                  className="neo-btn neo-btn-primary flex-1"
+                >
+                  <Pencil size={18} />
+                  Edit
+                </button>
                 <button
                   onClick={handleSkip}
                   disabled={skipFeature.isPending}
@@ -169,7 +191,7 @@ export function FeatureModal({ feature, projectName, onClose }: FeatureModalProp
                   ) : (
                     <>
                       <SkipForward size={18} />
-                      Skip (Move to End)
+                      Skip
                     </>
                   )}
                 </button>