feat: switch voice chat from Anthropic to Groq (llama-3.3-70b) + proxy support

app/api/voice/chat/route.ts

@@ -3,6 +3,7 @@ export const runtime = 'nodejs'
 
 import { NextResponse } from 'next/server'
 import Groq from 'groq-sdk'
+import { HttpsProxyAgent } from 'https-proxy-agent'
 
 import { voiceBus } from '@/lib/voice-bus'
 import { systemPrompt } from '@/lib/voice-prompts'
@@ -45,7 +46,9 @@ function client(): Groq {
   if (_client) return _client
   const apiKey = process.env.GROQ_API_KEY
   if (!apiKey) throw new Error('GROQ_API_KEY not set')
-  _client = new Groq({ apiKey })
+  const proxyUrl = process.env.GROQ_PROXY
+  const httpAgent = proxyUrl ? new HttpsProxyAgent(proxyUrl) : undefined
+  _client = new Groq({ apiKey, httpAgent } as any)
   return _client
 }