Introduce GEMINI_CLI_HOME for strict test isolation (#15907)

packages/a2a-server/src/commands/command-registry.ts

@@ -10,10 +10,15 @@ import { InitCommand } from './init.js';
 import { RestoreCommand } from './restore.js';
 import type { Command } from './types.js';
 
-class CommandRegistry {
+export class CommandRegistry {
   private readonly commands = new Map<string, Command>();
 
   constructor() {
+    this.initialize();
+  }
+
+  initialize() {
+    this.commands.clear();
     this.register(new ExtensionsCommand());
     this.register(new RestoreCommand());
     this.register(new InitCommand());