Activate Stack CLI 0.5.4 across distribution channels

[konojunya]

Background

Stack CLI 0.5.4 is now available from the immutable GitHub Release, crates.io, and the official Homebrew tap. The source repository still advertises 0.5.3 as the active release, and the Aqua smoke fixture still selects the previous archive set.

Implementation Approach

• Mark 0.5.4 as the active release in the machine-readable distribution contract and public installation guidance.
• Pin the Aqua fixture to the four published 0.5.4 archives and their verified SHA-256 checksums.
• Refresh the bundled Stack diagram skill from the final documentation revision.
• Keep package-manager ownership explicit: Homebrew, Aqua, and Cargo perform upgrades; the CLI does not self-update.

Release evidence:

• CLI source: 48028ac0588d5c1ce4fc10ce2df4ce260a39143e
• GitHub Release: https://github.com/stack-sh/cli/releases/tag/v0.5.4
• Cargo publication run: https://github.com/stack-sh/cli/actions/runs/34077379039
• Native release run: https://github.com/stack-sh/cli/actions/runs/34077764523
• Homebrew tap source: 1bd7b0e3c740dbfdcc7ef735863e336b69f815e9
• Homebrew main verification: https://github.com/stack-sh/homebrew-tap/actions/runs/34078298300
• Documentation source: 11af4fc57f53d903475d3619810a2885031d958c
• Documentation manifest SHA-256: be6cd48fcf50fc7c26c85eaf6869c8bf18cc3284e9638e26068641bed3af4672

Testing Approach

• npm run skills:check
• node scripts/validate-distribution-contract.mjs
• node --test scripts/*.test.mjs (82 tests)
• python3 -m unittest discover -s scripts -p "test_*.py" (15 tests)
• Rust 1.85 all-feature tests and Clippy with warnings denied
• cargo publish --locked --dry-run --allow-dirty
• Exact Aqua checksum inventory validation for all four release targets

Review Perspectives / Points of Concern

• The Aqua registry revision intentionally remains unchanged because its generic package mapping already supports 0.5.4; only the selected version and generated checksum lock advance.
• No immutable release artifact is replaced.