Add api server code and workflow

src/main.py

@@ -0,0 +1,16 @@
+from fastapi import FastAPI
+import sys
+sys.path.append('..')
+from api.endpoints import router as api_router
+
+app = FastAPI(
+    title="AI Accident Information Collection API",
+    description="AI Accident Information Collection API",
+    version="1.0.0"
+)
+
+@app.get("/")
+def read_root():
+    return {"message": "Server is running."}
+
+app.include_router(api_router)