feat(core): Add heartbeat grace/timeout options, client retry/wait-for-ready, server readiness and socket cleanup, transport socket options, helper utilities, and tests

ts/classes.transports.ts

@@ -34,6 +34,10 @@ export interface IIpcTransportOptions {
   noDelay?: boolean;
   /** Maximum message size in bytes (default: 8MB) */
   maxMessageSize?: number;
+  /** Automatically cleanup stale socket file on start (default: false) */
+  autoCleanupSocketFile?: boolean;
+  /** Socket file permissions mode (e.g. 0o600) */
+  socketMode?: number;
 }
 
 /**
@@ -206,11 +210,13 @@ export class UnixSocketTransport extends IpcTransport {
    */
   private async startServer(socketPath: string): Promise<void> {
     return new Promise((resolve, reject) => {
-      // Clean up stale socket file if it exists
-      try {
-        plugins.fs.unlinkSync(socketPath);
-      } catch (error) {
-        // File doesn't exist, that's fine
+      // Clean up stale socket file if autoCleanupSocketFile is enabled
+      if (this.options.autoCleanupSocketFile) {
+        try {
+          plugins.fs.unlinkSync(socketPath);
+        } catch (error) {
+          // File doesn't exist, that's fine
+        }
       }
 
       this.server = plugins.net.createServer((socket) => {
@@ -247,6 +253,15 @@ export class UnixSocketTransport extends IpcTransport {
       this.server.on('error', reject);
 
       this.server.listen(socketPath, () => {
+        // Set socket permissions if specified
+        if (this.options.socketMode !== undefined && process.platform !== 'win32') {
+          try {
+            plugins.fs.chmodSync(socketPath, this.options.socketMode);
+          } catch (error) {
+            // Ignore permission errors, not critical
+          }
+        }
+        
         this.connected = true;
         this.emit('connect');
         resolve();