fix: serialize the admin login lookup so concurrent first calls send one request

tests/test_auth.py

@@ -17,8 +17,13 @@ from aegis_gitea_mcp.auth import (
     StaticBearerVerifier,
 )
 from aegis_gitea_mcp.errors import ToolError
-from aegis_gitea_mcp.gitea import GiteaExecutor
-from tests.test_server_helpers import API, BEARER_TOKEN, GITEA_TOKEN, server_settings
+from aegis_gitea_mcp.gitea import GiteaExecutor, ToolOutcome
+from tests.test_server_helpers import (
+    API,
+    BEARER_TOKEN,
+    GITEA_TOKEN,
+    server_settings,
+)
 
 # Static bearer verifier
 
@@ -171,3 +176,23 @@ async def test_missing_gitea_token_is_refused() -> None:
 
     with pytest.raises(ToolError, match="GITEA_TOKEN"):
         await resolver.resolve(None)
+
+
+async def test_concurrent_first_calls_send_one_login_lookup() -> None:
+    import asyncio
+
+    lookups: list[str] = []
+
+    class SlowExecutor(GiteaExecutor):
+        async def request(self, method: str, path: str, *args: Any, **kwargs: Any) -> ToolOutcome:
+            lookups.append(path)
+            await asyncio.sleep(0.01)  # a real network round trip yields to other calls
+            return ToolOutcome(False, {"data": {"login": "admin"}}, 200)
+
+    settings = server_settings()
+    resolver = AdminIdentityResolver(settings, SlowExecutor(settings))
+
+    identities = await asyncio.gather(*(resolver.resolve(None) for _ in range(10)))
+
+    assert {identity.login for identity in identities} == {"admin"}
+    assert lookups == ["/user"]