fix: normalize nullable user profile fields (#73)

src/main.py

@@ -95,7 +95,7 @@ async def context() -> JSONResponse:
         }, headers={
             "Retry-After": str(max(1, math.ceil(CONTEXT_TIMEOUT_SECONDS)))
         } if isinstance(e, TimeoutError) else None)
-    user_model = User(id=user_data["id"], login=user_data["login"], full_name=user_data.get("full_name", ""), email=user_data.get("email", ""))
+    user_model = User(id=user_data["id"], login=user_data["login"], full_name=user_data.get("full_name") or "", email=user_data.get("email") or "")
     repo_models = [
         Repo(id=r["id"], name=r["name"], full_name=r["full_name"], description=r.get("description") or "", url=r["html_url"], updated_at=r.get("updated_at", ""))
         for r in (repo_data or [])[:50]