feat(a2a): add gRPC V1 support and robust agent card normalization

This consolidated commit implements comprehensive gRPC V1 support for A2A agents while maintaining high standards for type safety and encapsulation:

- gRPC V1 Protocol Bridge: Implemented a direct gRPC implementation in 'v1-bridge.ts' to support the V1 protocol ('tenant' at Tag 1, 'Message' at Tag 2). Fixed request mapping to avoid nested object issues and correctly handle streaming responses.
- Robust Card Normalization: Refactored 'a2aUtils.ts' to preserve all original agent card fields (ensuring SDK compatibility) while safely normalizing 'protocolBinding' to 'transport' for gRPC discovery.
- Orchestration Clean-up: Refactored 'A2AClientManager' to use high-level delegation, extracting SDK and V1-specific logic into clean helper methods. Removed all 'eslint-disable' markers through robust type guards and explicit object construction.
- Registry Stability: Refined 'AgentRegistry' to use the canonical agent name as the storage key, ensuring consistency even when local overrides are applied.
- Infrastructure: Integrated UndiciAgent with 30-minute timeouts for remote agent tasks and improved agent card URL resolution.
- Validation: Added a real-world integration test against a local Go server. Verified with 75 tests passing project-wide.

packages/a2a-server/src/config/config.ts

@@ -109,6 +109,8 @@ export async function loadConfig(
     interactive: !isHeadlessMode(),
     enableInteractiveShell: !isHeadlessMode(),
     ptyInfo: 'auto',
+    enableAgents: settings.experimental?.enableAgents ?? true,
+    agents: settings.agents,
   };
 
   const fileService = new FileDiscoveryService(workspaceDir, {

packages/a2a-server/src/config/settings.ts

@@ -14,6 +14,7 @@ import {
   getErrorMessage,
   type TelemetrySettings,
   homedir,
+  type AgentSettings,
 } from '@google/gemini-cli-core';
 import stripJsonComments from 'strip-json-comments';
 
@@ -45,6 +46,10 @@ export interface Settings {
     enableRecursiveFileSearch?: boolean;
     customIgnoreFilePaths?: string[];
   };
+  experimental?: {
+    enableAgents?: boolean;
+  };
+  agents?: AgentSettings;
 }
 
 export interface SettingsError {