fix: update supervisor.readLog to accept 3 parameters with logfile path

Update the readLog method to match custom Supervisor API requirements:
- Add third parameter (logfile_path) to supervisor.readLog call
- Retrieve logfile path from supervisor.getAPIVersion() metadata
- Cache logfile path after first retrieval to avoid repeated API calls
- Support optional explicit logfile_path parameter
- Fallback to default path if metadata extraction fails

Implementation details:
- Added cachedLogfilePath private field to SupervisorClient
- Added private getLogfilePath() method to extract path from API version
- Updated readLog signature: (offset, length, logfilePath?)
- Automatic path retrieval when logfilePath not provided
- Supports multiple metadata formats (logfile, logfile_path properties)
- Logs warnings if path extraction fails, uses sensible default

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

lib/supervisor/client.ts

@@ -25,6 +25,7 @@ export class SupervisorClient {
   private client: xmlrpc.Client;
   private config: SupervisorClientConfig;
   private logger: ReturnType<typeof createLogger>;
+  private cachedLogfilePath?: string;
 
   constructor(config: SupervisorClientConfig) {
     this.config = config;
@@ -101,6 +102,40 @@ export class SupervisorClient {
     return this.call<string>('supervisor.getSupervisorVersion');
   }
 
+  /**
+   * Get logfile path from API version metadata
+   * Caches the result after first call
+   */
+  private async getLogfilePath(): Promise<string> {
+    if (this.cachedLogfilePath) {
+      return this.cachedLogfilePath;
+    }
+
+    // Get API version which should contain logfile path in metadata
+    const apiVersionData = await this.call<any>('supervisor.getAPIVersion');
+
+    // Parse the response to extract logfile path
+    // The exact structure depends on your supervisor API implementation
+    // Common formats might be:
+    // - { version: "3.0", logfile: "/path/to/log" }
+    // - Just a string with embedded metadata
+    let logfilePath: string;
+
+    if (typeof apiVersionData === 'object' && apiVersionData.logfile) {
+      logfilePath = apiVersionData.logfile;
+    } else if (typeof apiVersionData === 'object' && apiVersionData.logfile_path) {
+      logfilePath = apiVersionData.logfile_path;
+    } else {
+      // Fallback to default supervisord log location if not found in metadata
+      this.logger.warn('Could not extract logfile path from getAPIVersion, using default');
+      logfilePath = '/var/log/supervisor/supervisord.log';
+    }
+
+    this.cachedLogfilePath = logfilePath;
+    this.logger.debug({ logfilePath }, 'Retrieved and cached logfile path');
+    return logfilePath;
+  }
+
   async getIdentification(): Promise<string> {
     return this.call<string>('supervisor.getIdentification');
   }
@@ -252,8 +287,10 @@ export class SupervisorClient {
     return this.call<ProcessActionResult[]>('supervisor.clearAllProcessLogs');
   }
 
-  async readLog(offset: number, length: number): Promise<string> {
+  async readLog(offset: number, length: number, logfilePath?: string): Promise<string> {
-    return this.call<string>('supervisor.readLog', [offset, length]);
+    // If logfilePath not provided, get it from API version metadata
+    const path = logfilePath || await this.getLogfilePath();
+    return this.call<string>('supervisor.readLog', [offset, length, path]);
   }
 
   async clearLog(): Promise<boolean> {