feat: Add NIP-47 Nostr Wallet Connect integration

Implements comprehensive wallet management system with NWC support:

- Install applesauce-wallet-connect for NIP-47 protocol handling
- Create WalletManager singleton service for connection management
  - Persistent localStorage storage for wallet connections
  - Support for multiple wallet connections with active wallet selection
  - Balance queries, invoice payments, and wallet info retrieval
- Add wallet command and parser for CLI-style interaction
  - `wallet` - Open wallet manager
  - `wallet connect <uri>` - Add NWC connection
  - Support for custom wallet names via --name flag
- Create WalletViewer component with full wallet management UI
  - List all wallet connections with balances
  - Add/remove wallet connections
  - Set active wallet
  - Visual connection status indicators
- Wire into window rendering and command system
- Add wallet icon to command icons

This provides the foundation for future payment features (zaps, nutzaps, etc.)
as discussed in the wallet/payment architecture planning.

package.json

@@ -49,6 +49,7 @@
     "applesauce-react": "^5.0.1",
     "applesauce-relay": "^5.0.0",
     "applesauce-signers": "^5.0.0",
+    "applesauce-wallet-connect": "^5.0.1",
     "blossom-client-sdk": "^4.1.0",
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",