test: add SimpleGitServer helper for dumb HTTP git serving

Add a test helper that serves git repositories over HTTP using git's
dumb HTTP protocol. This enables integration tests that need to fetch
git data from an external URL without requiring a full git HTTP backend.

Features:
- Creates bare clone of source repository
- Runs git update-server-info to generate required metadata
- Serves static files over HTTP using hyper
- Automatic cleanup on drop
- Path traversal protection

Tests included:
- Server starts and stops correctly
- info/refs endpoint is accessible
- git ls-remote works against server
- git fetch works against server
- Path traversal is blocked

This helper will be used in Phase 3 to test PR clone tag sync,
where the PR event's clone URL points to an external git server
that is NOT an ngit-grasp relay.

1 files changed, 2 insertions, 0 deletions

diff --git a/tests/common/mod.rs b/tests/common/mod.rs
index f511163..e70bd71 100644
--- a/tests/common/mod.rs
+++ b/tests/common/mod.rs
@@ -2,10 +2,12 @@
 #![allow(dead_code)] // Test helpers may not be used in all test configurations
 #![allow(unused_imports)] // Re-exports may not be used in all test configurations
 
+pub mod git_server;
 pub mod purgatory_helpers;
 pub mod relay;
 pub mod sync_helpers;
 
+pub use git_server::SimpleGitServer;
 pub use purgatory_helpers::*;
 pub use relay::TestRelay;
 pub use sync_helpers::*;