fix: normalize nullable repository descriptions (#54)

src/main.py

@@ -84,7 +84,7 @@ async def context() -> JSONResponse:
         } 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", ""))
     repo_models = [
-        Repo(id=r["id"], name=r["name"], full_name=r["full_name"], description=r.get("description", ""), url=r["html_url"], updated_at=r.get("updated_at", ""))
+        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[:50]
         if isinstance(r, dict)
     ]