Polish documentation and release validation for public launch

[icerain-cmd]

What changed

• clarified the README and installation paths for Claude Code, OpenAI Codex, and guidance-only Cursor use
• standardized the repository as 13 core research skills plus 1 Level 3 router
• reconciled the public release checklist, social copy, release notes, white paper, and documentation site
• removed a case-colliding duplicate documentation path and the stale release-candidate validation log
• made release validation reproducible across UTF-8, LF/CRLF, and case-sensitive or case-insensitive environments
• expanded the validate workflow to run all three validators and mkdocs build --strict

Why

The public repository passed its original Linux checks but was not reproducible from a normal Windows checkout. Default encoding caused two validators to stop, CRLF conversion invalidated every manifest checksum, and site/docs/DIFFERENCES.md collided with site/docs/differences.md. Public documentation also did not consistently distinguish tested agent harnesses from unverified installation guidance.

User and maintainer impact

New users now get complete project-local layouts, file-count checks, a nested-installation warning, a minimal first prompt, and a read-only pilot structure. Maintainers get cross-platform validation, path-case checks, deterministic manifest regeneration, and one protected CI check covering repository, integration, public-release, and MkDocs validation.

Cursor loading remains explicitly unverified because Cursor is not installed in the audit environment. The existing v1.0.0 tag and Release are unchanged; these fixes are suitable for a subsequent v1.0.1 patch.

Validation

• python scripts/validate_repository.py — PASS
• python scripts/run_integrated_tests.py — PASS
• python scripts/validate_public_release.py — PASS
• mkdocs build --strict — PASS using site/requirements.txt
• git diff --check — PASS
• git fsck --no-reflogs --full — PASS
• working-tree and reachable-history secret scans — PASS