Add NDK skill documentation and examples

- Introduced comprehensive documentation for the Nostr Development Kit (NDK) including an overview, quick reference, and troubleshooting guide.
- Added detailed examples covering initialization, authentication, event publishing, querying, and user profile management.
- Structured the documentation to facilitate quick lookups and deep learning, based on real-world usage patterns from the Plebeian Market application.
- Created an index for examples to enhance usability and navigation.
- Bumped version to 1.0.0 to reflect the addition of this new skill set.

.claude/skills/ndk/examples/README.md

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+# NDK Examples Index
+
+Complete code examples extracted from the Plebeian Market production codebase.
+
+## Available Examples
+
+### 01-initialization.ts
+- Basic NDK initialization
+- Multiple NDK instances (main + zap relays)
+- Connection with timeout protection
+- Connection status checking
+- Full initialization flow with error handling
+
+### 02-authentication.ts
+- NIP-07 browser extension login
+- Private key signer
+- NIP-46 remote signer (Bunker)
+- Auto-login from localStorage
+- Saving auth credentials
+- Logout functionality
+- Getting current user
+
+### 03-publishing-events.ts
+- Basic note publishing
+- Events with tags (mentions, hashtags, replies)
+- Product listings (parameterized replaceable events)
+- Order creation events
+- Status update events
+- Batch publishing
+- Custom signer usage
+- Comprehensive error handling
+
+### 04-querying-subscribing.ts
+- Basic fetch queries
+- Multiple author queries
+- Tag filtering
+- Time range filtering
+- Event ID lookup
+- Real-time subscriptions
+- Subscription cleanup patterns
+- React integration hooks
+- React Query integration
+- Waiting for specific events
+- Payment monitoring
+
+### 05-users-profiles.ts
+- Fetch profile by npub
+- Fetch profile by hex pubkey
+- Fetch profile by NIP-05
+- Universal identifier lookup
+- Get current user
+- Extract profile information
+- Update user profile
+- Batch fetch multiple profiles
+- Convert between pubkey formats (hex/npub)
+- React hooks for profiles
+- Follow/unfollow users
+
+## Usage
+
+Each file contains:
+- Fully typed TypeScript code
+- JSDoc comments explaining the pattern
+- Error handling examples
+- Integration patterns with React/TanStack Query
+- Real-world usage examples
+
+All examples are based on actual production code from the Plebeian Market application.
+
+## Running Examples
+
+```typescript
+import { initializeNDK } from './01-initialization'
+import { loginWithExtension } from './02-authentication'
+import { publishBasicNote } from './03-publishing-events'
+
+// Initialize NDK
+const { ndk, isConnected } = await initializeNDK()
+
+if (isConnected) {
+  // Authenticate
+  const { user } = await loginWithExtension(ndk)
+  
+  // Publish
+  await publishBasicNote(ndk, 'Hello Nostr!')
+}
+```
+
+## Additional Resources
+
+- See `../ndk-skill.md` for detailed documentation
+- See `../quick-reference.md` for quick lookup
+- Check the main codebase for more complex patterns
+