refactor: Implement lazy initialization for API clients

- Convert OpenAI and Hugging Face clients to use lazy initialization
- Reduce startup time by deferring client instantiation
- Maintain backward compatibility with proxy pattern
- Support all existing environment variable configurations

lib/hf-client.ts

@@ -1,6 +1,21 @@
 import OpenAI from "openai";
 
-export const hf = new OpenAI({
-  apiKey: process.env.HF_TOKEN,
-  baseURL: "https://router.huggingface.co/v1",
+let hfInstance: OpenAI | null = null;
+
+export function getHF(): OpenAI {
+  if (!hfInstance) {
+    hfInstance = new OpenAI({
+      apiKey: process.env.HF_TOKEN,
+      baseURL: "https://router.huggingface.co/v1",
+    });
+  }
+  return hfInstance;
+}
+
+// Export a getter that matches the original export name
+export const hf = new Proxy({} as OpenAI, {
+  get(_target, prop, _receiver) {
+    const client = getHF();
+    return Reflect.get(client, prop, client);
+  }
 });

lib/openai-client.ts

@@ -1,9 +1,24 @@
 import OpenAI from "openai";
 
-export const openai = new OpenAI({
-  apiKey: process.env.OPENAI_API_KEY || "",
-  baseURL: process.env.OPENAI_BASE_URL || undefined,
-  defaultHeaders: process.env.OPENAI_EXTRA_HEADERS
-    ? JSON.parse(process.env.OPENAI_EXTRA_HEADERS)
-    : undefined,
+let openaiInstance: OpenAI | null = null;
+
+export function getOpenAI(): OpenAI {
+  if (!openaiInstance) {
+    openaiInstance = new OpenAI({
+      apiKey: process.env.OPENAI_API_KEY || "",
+      baseURL: process.env.OPENAI_BASE_URL || undefined,
+      defaultHeaders: process.env.OPENAI_EXTRA_HEADERS
+        ? JSON.parse(process.env.OPENAI_EXTRA_HEADERS)
+        : undefined,
+    });
+  }
+  return openaiInstance;
+}
+
+// Export a getter that matches the original export name
+export const openai = new Proxy({} as OpenAI, {
+  get(_target, prop, _receiver) {
+    const client = getOpenAI();
+    return Reflect.get(client, prop, client);
+  }
 });