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.

lib/utils/log.ts

@@ -1,5 +1,30 @@
+import * as fs from "node:fs";
+import { promises as fsPromises } from "node:fs";
+import * as os from "node:os";
+import * as path from "node:path";
+
+const timeZero = Date.now();
+
 /**
  * Simple logging utility
  * @param message Message to log
+ * @param logFilePath Optional custom log file path
  */
-export function log(_message: string): void {}
+export function log(
+    message: string,
+    logFilePath: string = path.join(os.homedir(), ".mcp-code23.log")
+): void {
+    // Ensure the directory exists
+    const logDir = path.dirname(logFilePath);
+    fs.mkdirSync(logDir, { recursive: true });
+
+    const now = new Date();
+    const timestamp = new Date().toISOString();
+    const relativeTime = now.getTime() - timeZero;
+    const logMessage = `[${relativeTime}ms] ${timestamp} - ${message}\n`;
+    fs.appendFile(logFilePath, logMessage, (err) => {
+        if (err) {
+            console.error("Error writing to log file:", err);
+        }
+    });
+}