Refactor: Centralize GeminiClient in Config (#693)

Co-authored-by: N. Taylor Mullen <ntaylormullen@google.com>

packages/core/src/config/config.ts

@@ -21,6 +21,7 @@ import { WebFetchTool } from '../tools/web-fetch.js';
 import { ReadManyFilesTool } from '../tools/read-many-files.js';
 import { MemoryTool, setGeminiMdFilename } from '../tools/memoryTool.js';
 import { WebSearchTool } from '../tools/web-search.js';
+import { GeminiClient } from '../core/client.js';
 import { GEMINI_CONFIG_DIR as GEMINI_DIR } from '../tools/memoryTool.js';
 
 export enum ApprovalMode {
@@ -86,6 +87,7 @@ export class Config {
   private approvalMode: ApprovalMode;
   private readonly vertexai: boolean | undefined;
   private readonly showMemoryUsage: boolean;
+  private readonly geminiClient: GeminiClient;
 
   constructor(params: ConfigParameters) {
     this.apiKey = params.apiKey;
@@ -112,6 +114,7 @@ export class Config {
     }
 
     this.toolRegistry = createToolRegistry(this);
+    this.geminiClient = new GeminiClient(this);
   }
 
   getApiKey(): string {
@@ -200,6 +203,10 @@ export class Config {
   getShowMemoryUsage(): boolean {
     return this.showMemoryUsage;
   }
+
+  getGeminiClient(): GeminiClient {
+    return this.geminiClient;
+  }
 }
 
 function findEnvFile(startDir: string): string | null {