Introduce CLI health and shell setup in Getting Started

[konojunya]

Background

Getting Started stopped after the first render and formatting loop. The released CLI also provides read-only installation diagnosis, configuration discovery, shell completion generation, and an offline manual, but new users could only discover them through a final link.

Implementation Approach

• Add a post-render CLI setup section to all four locale sources.
• Explain the safe, read-only behavior of stack doctor and stack config path.
• Show the bash, zsh, and fish completion generators plus stack manpage.
• Distinguish Homebrew-managed files from user-owned setup for Direct, Aqua, and Cargo.
• Keep the detailed per-shell paths in the CLI contract and preserve one canonical link.
• Regenerate only the four affected pages and their manifest hashes.
• Extend the first-render contract test so these commands cannot disappear or drift between locales.

Testing Approach

• npm run generate
• npm test (22 tests)
• npm run check
• npm run machine:check
• STACK_CLI_BIN=/absolute/path/to/stack npm run smoke against the published CLI 0.5.2
• Verified four-locale first render and generated skill commands.

Review Perspectives / Points of Concern

Please verify that the added commands are useful immediately after first render, that they do not imply automatic dotfile changes, and that the four translations preserve identical command blocks.