v0.9.1

Changed

• Release pipeline migrated to canonical reusable workflow at
  arthur-debert/release/.github/workflows/rust-cli.yml@v1. lex's
  .github/workflows/release.yml is now a thin caller. Sixth and final
  consumer of the new pipeline (after dodot v2.0.0, padz v1.8.2,
  simple-gal v0.20.4, rustloc v0.14.2, burgertocow v0.3.1 — all verified
  end-to-end). Bug fixes propagate via a single bump of the action's
  @v1 ref instead of hand-edits across 6 rust-CLIs.
• Tarball naming + layout changed to canonical (full target triples +
  subdir layout). Brew formula handles both layouts.
• Intel-mac dropped from release artifacts (x86_64-apple-darwin)
  for both lexd and lexd-lsp. arm64-only macOS by canonical convention.
  v0.9.0 and earlier remain available for Intel users via direct GH
  release download.
• CHANGELOG section headers migrated to Keep-a-Changelog canonical
  bracketed form (## [Unreleased], ## [0.9.0] - DATE instead of
  ## Unreleased, ## 0.9.0 - DATE). The action's prepare-release
  expects the bracketed form. Existing version section bodies are
  untouched.