Phase 1 review checkpoint fixes: - Added #[cfg(feature = "quinn")] to build_quinn_server_config_from_rustls and build_quinn_client_config_* tests (for_quinn is feature-gated) - Ran cargo fmt for consistent formatting - All 34 tests pass across all feature combos (default, no-default, all-features) - Workspace fully green: cargo test --workspace, cargo clippy, cargo fmt