Add dev/vcpkg to workflow triggers for testing

Temporarily add dev/vcpkg branch to CI triggers to test
vcpkg binary caching setup. Can be removed before merging
to main.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: rmpowell77

.github/workflows/cmake.yml

@@ -9,6 +9,7 @@ on:
     branches:
     - main
     - calchart-3.6
+    - dev/vcpkg
     tags:
     - '*'
   pull_request: