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

Commit B fixes a real deadlock bug (holding a RwLock guard across nested read/write calls in RPC handlers) plus adds timeouts to prevent test hangs and corrects test assertions to match actual stored username format, all substantive correctness fixes with a new integration test. Commit A is a small, clean, well-tested feature addition (skip pinned posts), but is narrower in scope and impact compared to B's deadlock fix which addresses a potentially serious production issue.