feat: automatic /model persistence across Gemini CLI sessions (#13199)

Co-authored-by: Jack Wotherspoon <jackwoth@google.com>

packages/cli/src/config/config.ts

@@ -35,6 +35,7 @@ import {
   PREVIEW_GEMINI_MODEL_AUTO,
 } from '@google/gemini-cli-core';
 import type { Settings } from './settings.js';
+import { saveModelChange, loadSettings } from './settings.js';
 
 import { loadSandboxConfig } from './sandboxConfig.js';
 import { resolvePath } from '../utils/resolvePath.js';
@@ -387,6 +388,8 @@ export async function loadCliConfig(
 ): Promise<Config> {
   const debugMode = isDebugMode(argv);
 
+  const loadedSettings = loadSettings(cwd);
+
   if (argv.sandbox) {
     process.env['GEMINI_SANDBOX'] = 'true';
   }
@@ -693,6 +696,7 @@ export async function loadCliConfig(
     // TODO: loading of hooks based on workspace trust
     enableHooks: settings.tools?.enableHooks ?? false,
     hooks: settings.hooks || {},
+    onModelChange: (model: string) => saveModelChange(loadedSettings, model),
   });
 }