Refactor API structure: move chat functionality to v1 router, implement dependency injection for OpenAI client, and set up application state management

core/config.py

@@ -0,0 +1,7 @@
+from dotenv import load_dotenv
+from pathlib import Path
+import os
+
+load_dotenv(Path(__file__).resolve().parent.parent / ".env")
+
+DEEPSEEK_API_KEY = os.getenv("DEEPSEEK_API_KEY")

core/llm.py

@@ -0,0 +1,9 @@
+from openai import OpenAI
+
+
+def create_client(api_key: str) -> OpenAI:
+    """Factory for an OpenAI-compatible client pointed at DeepSeek."""
+    return OpenAI(
+        api_key=api_key,
+        base_url="https://api.deepseek.com",
+    )