chore: mark US-022 as complete and update progress log

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

prd.json

@@ -390,7 +390,7 @@
         "Verify in browser using dev-browser skill"
       ],
       "priority": 22,
-      "passes": false,
+      "passes": true,
       "notes": ""
     },
     {

progress.txt

@@ -338,3 +338,16 @@
   - Node creation pattern: create Node object with { id, type, position, data }, then add to state via setNodes
   - React Flow nodes are draggable by default, no extra configuration needed
 ---
+
+## 2026-01-21 - US-022
+- What was implemented: Custom ChoiceNode component for displaying branching decisions
+- Files changed:
+  - src/components/editor/nodes/ChoiceNode.tsx - new custom node component with green styling, editable prompt, and dynamic option handles
+  - src/app/editor/[projectId]/FlowchartEditor.tsx - registered ChoiceNode as custom node type
+- **Learnings for future iterations:**
+  - ChoiceNode follows same pattern as DialogueNode: NodeProps<T> typing, useReactFlow() for updates
+  - Dynamic handles positioned using style={{ left: `${((index + 1) / (options.length + 1)) * 100}%` }} for even spacing
+  - Handle id format for options: 'option-0', 'option-1', etc. (matching the index)
+  - Each option needs a unique id (string) and label (string) per the ChoiceOption type
+  - updateOptionLabel callback pattern: find option by id, map over options array to update matching one
+---