refactor: flatten Microsoft skills from nested to flat directory structure

Rewrote sync_microsoft_skills.py (v4) to use each SKILL.md's frontmatter
'name' field as the flat directory name under skills/, replacing the nested
skills/official/microsoft/<lang>/<category>/<service>/ hierarchy.

This fixes CI failures caused by the indexing, validation, and catalog
scripts expecting skills/<id>/SKILL.md (depth 1).

Changes:
- Rewrite scripts/sync_microsoft_skills.py for flat output with collision detection
- Update scripts/tests/inspect_microsoft_repo.py for flat name mapping
- Update scripts/tests/test_comprehensive_coverage.py for name uniqueness checks
- Delete skills/official/ nested directory
- Add 129 Microsoft skills as flat directories (e.g. skills/azure-mgmt-botservice-dotnet/)
- Move attribution files to docs/ (LICENSE-MICROSOFT, microsoft-skills-attribution.json)
- Rebuild skills_index.json, CATALOG.md, README.md (845 total skills)

skills/react-flow-node-ts/SKILL.md

@@ -0,0 +1,66 @@
+---
+name: react-flow-node-ts
+description: Create React Flow node components with TypeScript types, handles, and Zustand integration. Use when building custom nodes for React Flow canvas, creating visual workflow editors, or implementing node-based UI components.
+---
+
+# React Flow Node
+
+Create React Flow node components following established patterns with proper TypeScript types and store integration.
+
+## Quick Start
+
+Copy templates from [assets/](assets/) and replace placeholders:
+- `{{NodeName}}` → PascalCase component name (e.g., `VideoNode`)
+- `{{nodeType}}` → kebab-case type identifier (e.g., `video-node`)
+- `{{NodeData}}` → Data interface name (e.g., `VideoNodeData`)
+
+## Templates
+
+- [assets/template.tsx](assets/template.tsx) - Node component
+- [assets/types.template.ts](assets/types.template.ts) - TypeScript definitions
+
+## Node Component Pattern
+
+```tsx
+export const MyNode = memo(function MyNode({
+  id,
+  data,
+  selected,
+  width,
+  height,
+}: MyNodeProps) {
+  const updateNode = useAppStore((state) => state.updateNode);
+  const canvasMode = useAppStore((state) => state.canvasMode);
+  
+  return (
+    <>
+      <NodeResizer isVisible={selected && canvasMode === 'editing'} />
+      <div className="node-container">
+        <Handle type="target" position={Position.Top} />
+        {/* Node content */}
+        <Handle type="source" position={Position.Bottom} />
+      </div>
+    </>
+  );
+});
+```
+
+## Type Definition Pattern
+
+```typescript
+export interface MyNodeData extends Record<string, unknown> {
+  title: string;
+  description?: string;
+}
+
+export type MyNode = Node<MyNodeData, 'my-node'>;
+```
+
+## Integration Steps
+
+1. Add type to `src/frontend/src/types/index.ts`
+2. Create component in `src/frontend/src/components/nodes/`
+3. Export from `src/frontend/src/components/nodes/index.ts`
+4. Add defaults in `src/frontend/src/store/app-store.ts`
+5. Register in canvas `nodeTypes`
+6. Add to AddBlockMenu and ConnectMenu