feat: Add zap command for sending Bitcoin Lightning tips

- Implemented the `zap` command in the CLI to allow users to send sats to a user, event, or snippet using a NIP-60 wallet.
- Created a new `zap.ts` file to handle the command logic and integrated it into the MCP server.
- Added wallet balance command to check the balance of a user's wallet.
- Enhanced the MCP server to register the new zap command and wallet balance command.
- Introduced caching for wallets to optimize performance and reduce redundant network requests.
- Updated database schema to include snippets table for storing code snippets.
- Improved logging functionality for better debugging and tracking of operations.
- Added functionality to save snippets to the database upon retrieval.
- Updated project overview documentation to reflect new features and structure.
- Refactored existing commands and logic for better modularity and maintainability.

db.ts

@@ -31,6 +31,7 @@ export const migrations: Migration[] = [
     // Example:
     // { name: '001_initial_schema', module: () => import('./migrations/001_initial_schema.js') },
     // Add all migrations here
+    { name: '003-create-snippets-table', module: () => import('./migrations/003-create-snippets-table.js') },
 ];
 
 /**