test(docs): align README contracts with authoring preview boundaries

[777genius]

README classification introduced in the Phase 6 stack left two repository contract tests asserting obsolete current-authoring prose. Update the tests to verify the separate Use journey, unreleased standard Build preview, and preserved v1 capabilities within their historical section. Normalize CRLF before splitting that section so the same contract works on Windows checkouts.

Three test files change. Existing runtime/SDK assertions, all eight starter mappings, negative assertions, legacy implementations and README content remain intact. Sixteen boundary cases cover LF/CRLF and reject missing or incorrect boundaries.

Stacked on #181 at 6549f83; follows README classification in #178. Do not merge directly to main ahead of this stack.

Validation at 1643476:

• Independent medium reviews accepted both bounded patches with no findings. Actual contracts pass in independently created LF and CRLF filesystem fixtures; missing/wrong boundaries fail as expected.
• Polyglot Smoke 34141201189 passed on Windows and Linux, including both source-acquisition jobs. This closes the Windows README boundary regression observed on the preceding head.
• Authoring native offline 34141201270 passed all four Linux/Windows native jobs, packed Linux amd64 and the required aggregate.
• Relative README links and immutable v1.2.4 source references were validated offline; diff checks passed.

These checks qualify the bounded regression fix, not public activation or full Phase 6 release. Writable macOS support and the remaining release gates are still unproven.

[coderabbitai]

Important

Draft PR not reviewed

Draft PRs are not automatically reviewed by default.

• Trigger a manual review

To automatically review draft PRs, update your CodeRabbit configuration:

reviews:
  auto_review:
    drafts: true

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}