## What changed
- Add a Tree-sitter-based lowerer that converts a conservative subset of literal PowerShell commands into argument vectors.
- Reject dynamic expressions, parse recovery, unsupported value conversions, directives, and source outside recognized command nodes instead of guessing their meaning.
- Keep the lowerer alongside the existing production parser for later adoption.
## Testing
- Add fixture-driven coverage for supported literal commands and unsupported or ambiguous syntax, including a dedicated `#requires` rejection test.
GitOrigin-RevId: a6e7acc264ca40df264db4b271e38ae7d89e1ec4
## Intent
Keep Bazel and Starlark files consistently formatted without requiring
contributors to install or version buildifier themselves.
## Implementation
- Add a SHA-256-pinned, cross-platform DotSlash manifest for buildifier
v8.5.1.
- Run buildifier from the shared `just fmt` and `just fmt-check` driver,
with Windows-safe explicit DotSlash invocation.
- Provision DotSlash in formatting CI and contributor devcontainers, and
document the source-build prerequisite.
- Apply the initial mechanical buildifier formatting baseline.
