py(deps[libvcs]) Track subprocess-trimming branch (preview)

why: Validate the downstream impact of libvcs's verbatim-default
output capture (vcs-python/libvcs#538) before it ships in a release.

what:
- Pin libvcs to the branch via [tool.uv.sources].
- Update uv.lock to the branch build.

Author: tony

pyproject.toml

@@ -161,6 +161,12 @@ sphinx-gp-theme = false
 sphinx-ux-autodoc-layout = false
 sphinx-ux-badges = false
 
+[tool.uv.sources]
+# Preview: track the in-development libvcs ``subprocess-trimming`` branch
+# (verbatim-default output capture) to validate downstream impact. Remove
+# once libvcs ships the change in a release.
+libvcs = { git = "https://github.com/vcs-python/libvcs.git", branch = "subprocess-trimming" }
+
 [tool.mypy]
 python_version = "3.10"
 warn_unused_configs = true