fix: prediction proxy target을 nginx 경유로 변경

로컬 dev에서 192.168.1.18(redis-211 내부 IP) 직접 접근 불가 → timeout.
kcg.gc-si.dev nginx 경유로 변경하여 정상 동작.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/vite.config.ts

@@ -125,9 +125,9 @@ export default defineConfig(({ mode }): UserConfig => ({
         secure: true,
       },
       '/api/prediction/': {
-        target: 'http://192.168.1.18:8001',
+        target: 'https://kcg.gc-si.dev',
         changeOrigin: true,
-        rewrite: (path) => path.replace(/^\/api\/prediction/, '/api'),
+        secure: true,
       },
       '/ollama': {
         target: 'http://localhost:11434',