Refactor agent API structure and add core functionality with FastAPI integration

agent_api/main.py

@@ -0,0 +1,32 @@
+from fastapi import FastAPI
+from pydantic import BaseModel
+
+from .core.llm import client
+
+app = FastAPI()
+
+
+# ---- request model ----
+class ChatRequest(BaseModel):
+    message: str
+
+
+# ---- basic health check ----
+@app.get("/")
+def root():
+    return {"status": "ok"}
+
+
+# ---- test LLM endpoint ----
+@app.post("/chat")
+def chat(req: ChatRequest):
+    response = client.chat.completions.create(
+        model="deepseek-chat",
+        messages=[
+            {"role": "user", "content": req.message}
+        ]
+    )
+
+    return {
+        "response": response.choices[0].message.content
+    }