Make beta release documentation reproducible

[crimson-knight]

Summary

• Replace stale Homebrew commands in the reusable release checklist and release SOP.
• Document the tap bot's required explicit validation dispatch.
• Require the complete generated-web-app smoke path and macOS OpenSSL linkage check.
• Replace obsolete generator help links with public guides pinned to framework 2.0.0-beta.2.
• Expand the beta documentation contract to cover release-maintainer files and CLI-emitted links.

Validation

• bash scripts/check_beta_contract.sh
• crystal tool format --check src spec
• crystal spec (406 examples, 0 failures)
• Every pinned framework guide URL returns HTTP success.
• git diff --check

Release impact

Future releases and generated code now use the same trusted Homebrew command, support matrix, and guide versions as CLI 2.0.2.