feat(33-02): implement workflow edit safety - snapshot capture and revert UI

Tasks 1 & 2: Complete AI workflow revert feature

Changes:
- WorkflowCanvas: Call captureSnapshot() before AI loadWorkflow
- Header: Add "Revert AI Changes" button with confirmation dialog
- Button visible only when previousWorkflowSnapshot exists
- Amber styling to distinguish safety feature from destructive actions

Snapshot capture ONLY in AI generation path (not file loads/templates).
Button auto-hides after revert or 3 manual changes (store handles this).

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

.planning/ROADMAP.md

@@ -467,7 +467,7 @@ Plans:
 
 Plans:
 - [x] 32-01: ChatPanel component with useChat hook, WorkflowCanvas integration
-- [ ] 32-02: Chat context and workflow generation integration
+- [x] 32-02: Chat context and workflow generation integration
 
 #### Phase 33: Workflow Edit Safety
 
@@ -477,8 +477,11 @@ Plans:
 **Research topics**: Shadow copy vs diff-based vs undo stack approaches, JSON diff visualization
 **Plans**: TBD
 
+**Plans**: 2 plans
+
 Plans:
-- [ ] 33-01: TBD (run /gsd:plan-phase 33 to break down)
+- [ ] 33-01-PLAN.md — Store snapshot state, capture/revert/clear actions, manual change tracking
+- [ ] 33-02-PLAN.md — Wire snapshot capture in AI flow, Revert AI Changes button in Header
 
 #### Phase 34: Agentic Workflow Editing
 
@@ -651,7 +654,7 @@ Phases execute in numeric order: 1 → 2 → ... → 35 → 36 → 37 → 38 →
 | 29. Canvas Performance | v1.3 | 0/0 | Deferred | - |
 | 30. Small Fixes | v1.3 | 0/0 | Deferred | - |
 | 31. Workflow Proposal System | v1.4 | 2/2 | Complete | 2026-01-26 |
-| 32. Chat UI Foundation | v1.4 | 1/2 | In progress | - |
+| 32. Chat UI Foundation | v1.4 | 2/2 | Complete | 2026-01-27 |
 | 33. Workflow Edit Safety | v1.4 | 0/? | Not started | - |
 | 34. Agentic Workflow Editing | v1.4 | 0/? | Not started | - |
 | 35. Large Workflow Handling | v1.4 | 0/? | Not started | - |

src/components/Header.tsx

@@ -67,6 +67,8 @@ export function Header() {
     setWorkflowMetadata,
     saveToFile,
     loadWorkflow,
+    previousWorkflowSnapshot,
+    revertToSnapshot,
   } = useWorkflowStore();
 
   const [showProjectModal, setShowProjectModal] = useState(false);
@@ -157,6 +159,15 @@ export function Header() {
     }
   };
 
+  const handleRevertAIChanges = useCallback(() => {
+    const confirmed = window.confirm(
+      "Are you sure? This will restore your previous workflow."
+    );
+    if (confirmed) {
+      revertToSnapshot();
+    }
+  }, [revertToSnapshot]);
+
   return (
     <>
       <ProjectSetupModal
@@ -357,6 +368,15 @@ export function Header() {
         </div>
 
         <div className="flex items-center gap-3 text-xs">
+          {previousWorkflowSnapshot && (
+            <button
+              onClick={handleRevertAIChanges}
+              className="px-2.5 py-1 text-xs font-medium text-amber-300 bg-amber-500/15 hover:bg-amber-500/25 border border-amber-500/30 rounded transition-colors"
+              title="Restore workflow from before AI changes"
+            >
+              Revert AI Changes
+            </button>
+          )}
           <CommentsNavigationIcon />
           <span className="text-neutral-400">
             {isProjectConfigured ? (

src/components/WorkflowCanvas.tsx

@@ -179,7 +179,7 @@ const findScrollableAncestor = (target: HTMLElement, deltaX: number, deltaY: num
 };
 
 export function WorkflowCanvas() {
-  const { nodes, edges, groups, onNodesChange, onEdgesChange, onConnect, addNode, updateNodeData, loadWorkflow, getNodeById, addToGlobalHistory, setNodeGroupId, executeWorkflow, isModalOpen, showQuickstart, setShowQuickstart, navigationTarget, setNavigationTarget } =
+  const { nodes, edges, groups, onNodesChange, onEdgesChange, onConnect, addNode, updateNodeData, loadWorkflow, getNodeById, addToGlobalHistory, setNodeGroupId, executeWorkflow, isModalOpen, showQuickstart, setShowQuickstart, navigationTarget, setNavigationTarget, captureSnapshot } =
     useWorkflowStore();
   const { screenToFlowPosition, getViewport, zoomIn, zoomOut, setViewport, setCenter } = useReactFlow();
   const { show: showToast } = useToast();
@@ -579,6 +579,7 @@ export function WorkflowCanvas() {
       const data = await response.json();
 
       if (data.success && data.workflow) {
+        captureSnapshot(); // Capture BEFORE loading new workflow
         await loadWorkflow(data.workflow);
         setIsChatOpen(false);
         showToast("Workflow generated successfully", "success");
@@ -591,7 +592,7 @@ export function WorkflowCanvas() {
     } finally {
       setIsBuildingWorkflow(false);
     }
-  }, [loadWorkflow, showToast]);
+  }, [loadWorkflow, showToast, captureSnapshot]);
 
   // Handle node selection from drop menu
   const handleMenuSelect = useCallback(