Remove no-op dispose() method

Since ControlPersist=60 handles all socket cleanup automatically
and dispose() is not part of the Runtime interface or called anywhere,
there's no reason to keep an empty method.

Author: ammar-agent

src/runtime/SSHRuntime.ts

@@ -895,18 +895,6 @@ export class SSHRuntime implements Runtime {
       return { success: false, error: `Failed to delete directory: ${getErrorMessage(error)}` };
     }
   }
-
-  /**
-   * Cleanup SSH control socket on disposal.
-   *
-   * Note: This is a no-op because:
-   * - ControlPersist=60 automatically removes socket 60s after last use
-   * - Multiple SSHRuntime instances may share the same connection
-   * - Explicit cleanup could interfere with other active operations
-   */
-  dispose(): void {
-    // No-op: Let ControlPersist handle cleanup automatically
-  }
 }
 
 /**

src/runtime/sshConnectionPool.ts

@@ -23,6 +23,10 @@ import type { SSHRuntimeConfig } from "./SSHRuntime";
  * Socket files are created by SSH and cleaned up automatically:
  * - ControlPersist=60: Removes socket 60s after last use
  * - OS: Cleans /tmp on reboot
+ *
+ * Includes local username in hash to prevent cross-user collisions on
+ * multi-user systems (different users connecting to same remote would
+ * otherwise generate same socket path, causing permission errors).
  */
 export function getControlPath(config: SSHRuntimeConfig): string {
   const key = makeConnectionKey(config);
@@ -33,9 +37,11 @@ export function getControlPath(config: SSHRuntimeConfig): string {
 /**
  * Generate stable key from config.
  * Identical configs produce identical keys.
+ * Includes local username to prevent cross-user socket collisions.
  */
 function makeConnectionKey(config: SSHRuntimeConfig): string {
   const parts = [
+    os.userInfo().username, // Include local user to prevent cross-user collisions
     config.host,
     config.port?.toString() ?? "22",
     config.srcBaseDir,