feat: initialize project with FastAPI backend and OpenRouter chat integration

.gitignore

@@ -8,5 +8,4 @@ wheels/
 
 # Virtual environments
 .venv
-main.py
 .env

main.py

@@ -0,0 +1,51 @@
+import os
+from fastapi import FastAPI
+from fastapi.staticfiles import StaticFiles
+from fastapi.responses import FileResponse, StreamingResponse
+from pydantic import BaseModel
+from openai import OpenAI
+from dotenv import load_dotenv
+
+load_dotenv()
+
+client = OpenAI(
+    base_url="https://openrouter.ai/api/v1",
+    api_key=os.getenv("OPENROUTER_API_KEY"),
+)
+
+app = FastAPI(title="Simple Chatbot")
+
+
+class Message(BaseModel):
+    role: str
+    content: str
+
+
+class ChatRequest(BaseModel):
+    messages: list[Message]
+
+
+@app.post("/api/chat")
+async def chat(request: ChatRequest):
+    """Stream a chat completion from OpenRouter."""
+
+    def generate():
+        stream = client.chat.completions.create(
+            model="openrouter/free",
+            messages=[m.model_dump() for m in request.messages],
+            stream=True,
+        )
+        for chunk in stream:
+            if chunk.choices and chunk.choices[0].delta.content:
+                yield chunk.choices[0].delta.content
+
+    return StreamingResponse(generate(), media_type="text/plain")
+
+
+# Serve the frontend
+app.mount("/static", StaticFiles(directory="static"), name="static")
+
+
+@app.get("/")
+async def root():
+    return FileResponse("static/index.html")