Bump merge-queue mdsmith binary to v0.15.0 (#289)

Agent-Logs-Url: https://github.com/jeduden/mdsmith/sessions/35c9024b-75ca-4404-8e3b-a2079ce8b2d8

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: jeduden <1117699+jeduden@users.noreply.github.com>

Author: Copilot

.github/workflows/merge-queue.yml

@@ -37,8 +37,8 @@ jobs:
 
       - name: Install mdsmith merge driver and pre-merge-commit hook
         env:
-          MDSMITH_VERSION: v0.12.0
-          MDSMITH_SHA256: a93f966ae68447b5de18fbb3d57f4a6122f5d364a91341e31fd7cfc3c3881f48
+          MDSMITH_VERSION: v0.15.0
+          MDSMITH_SHA256: e91115916132c668620bb605bd162c05343aad26c3ed2c25e58c86a8506af191
         run: |
           # Install to a stable path that will persist for the hook to use
           mkdir -p "$HOME/.local/bin"