~anthropic/claude-sonnet-latest → A (6:4)

Side A fixes concrete, crash-causing bugs (string split needing a regex arg, wrong HttpExchange method for reading POST bodies, missing null guards, unhandled exceptions crashing the mock server) that were breaking the OAuth e2e test suite, directly restoring test reliability. Side B is a legitimate but debatable refactor (Deque->Vec/List, deferred capping) that trades write-time bounded storage for unbounded growth capped only at read time, which is a real design tradeoff rather than a clear correctness win, despite including a new test.