Add OpenRouter auto and free model router presets

Add the two built-in OpenRouter router presets to the existing
OpenRouter API model list.

Reference:
- https://openrouter.ai/openrouter/auto
- https://openrouter.ai/openrouter/free

Author: PeterDaveHello

src/config/index.mjs

@@ -111,6 +111,8 @@ export const moonshotApiModelKeys = [
 ]
 export const deepSeekApiModelKeys = ['deepseek_chat', 'deepseek_reasoner']
 export const openRouterApiModelKeys = [
+  'openRouter_auto',
+  'openRouter_free',
   'openRouter_google_gemini_3_pro',
   'openRouter_google_gemini_3_flash',
   'openRouter_google_gemini_3_1_pro',
@@ -407,6 +409,14 @@ export const Models = {
     value: 'anthropic/claude-3.7-sonnet',
     desc: 'OpenRouter (Claude 3.7 Sonnet)',
   },
+  openRouter_auto: {
+    value: 'openrouter/auto',
+    desc: 'OpenRouter (Auto Router)',
+  },
+  openRouter_free: {
+    value: 'openrouter/free',
+    desc: 'OpenRouter (Free Models Router)',
+  },
   openRouter_google_gemini_3_pro: {
     value: 'google/gemini-3-pro-preview',
     desc: 'OpenRouter (Gemini 3 Pro)',