fix(skills): repair machine-absolute and dangling relative links + link gate

[korallis]

What

Fixes the broken skill links reported in #78, at the source, plus a regression gate.

Changes

Source fixes (skills/)

• elaborate-spec, plan-release: file:///Users/danielvm/.../countable-story-format.md → GitHub blob URL. docs/ is .npmignored, so the file can never be linked relatively in published installs; the blob URL works everywhere.
• evolve-skill/REFERENCE.md: hardcoded `/Users/danielvm/Developer/bigpowers-benchmark/` → machine-agnostic clone resolution guidance.
• craft-skill, investigate-bug, plan-refactor: docs/ links (PRINCIPLES.md, model-profiles.md, feathers.md, fowler.md, kent-beck.md) → blob URLs (same npm-exclusion problem).
• using-bigpowers: ../profiles/solo-git.md → ../../profiles/solo-git.md (was dangling even in-repo).
• write-document/REFERENCE.md: CHANGELOG.md/LICENSE → repo-root-relative.
• guard-git: [hooks/](hooks/) → [REFERENCE.md](REFERENCE.md) — the hook bundle lives inline in REFERENCE.md; no hooks/ dir exists.
• audit-code: dropped a dead REFERENCE.md link (the --parallel helper script path is already given inline).
• grill-me/REFERENCE.md, model-domain/CONTEXT-FORMAT.md: de-linked illustrative example paths ([docs](URL), ./src/*/CONTEXT.md) that were never meant to resolve.

Renderer fix (the ~40 dangling REFERENCE.md links in .pi/skills/)

• scripts/lib/srp-engine.py: new rewrite_links_for_pi() — relative links in rendered pi skills are repointed from .pi/skills/<name>/ to the shipped source tree (../../../skills/<name>/X, ../../../CHANGELOG.md, …). Content was already inlined by parse_skill(); now the links resolve too, in repo checkouts and npm installs alike. External/anchor/absolute links pass through.
• scripts/adapters/pi.sh: renders skill files from the new body_pi_skill IR field; .pi/prompts output is unchanged apart from source edits.

Regression gate

• scripts/check-skill-links.py: fails on machine-absolute paths (file:///, /Users/, /home/, C:\Users) and on any dangling relative link in skills/**/SKILL.md and .pi/skills/**/SKILL.md. Wired into the compliance npm script; also runnable standalone as check:skill-links.
• .pi/skills/ regenerated via sync-skills.sh; python3 scripts/check-skill-links.py → OK — no machine paths or dangling links (was 45+ before this change).

Notes

• Rendered .cursor/rules / .gemini / .pi/prompts changes are just sync-skills.sh output reflecting the source edits.
• Out of scope (pre-existing, same wart, not part of fix: hardcoded author absolute paths + stripped reference files break 45+ links in .pi/skills tree #78): links inlined into .cursor/.gemini renderings still dangle there; those trees aren't published to npm. The new rewriter is the obvious place to extend if wanted.

Fixes #78

[danielvm-git]

Code Review — Dual-Blind AND-gate: ❌ FAIL (Round 1/5)

Two independent reviewers scored this PR 33% and 62.5% respectively. Both are below the 94% merge threshold. Requesting changes before merge.

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🔴 Must-Fix (3)

[A-1] LINK_RE matches inside fenced code blocks
Both rewrite_links_for_pi and check-skill-links.py apply LINK_RE to raw Markdown including fenced code blocks and inline code. check-skill-links.py will emit false-positive "dangling link" errors on example paths shown in code blocks; rewrite_links_for_pi will silently corrupt those examples in rendered output. Code block content must be stripped before link matching.

[A-2] LINK_RE silently drops links with title attributes
[text](target "Title") — the [^)\s]+ pattern stops at the space before the title. These links escape both the rewriter and the regression gate silently. Fix: r'\[([^\]]*)\]\(([^)\s"]+)(?:\s+"[^"]*")?\s*\)'

[B-1] DRY violation — LINK_RE + EXTERNAL_RE duplicated across two files
scripts/lib/srp-engine.py and scripts/check-skill-links.py independently define identical pattern constants. CONVENTIONS.md mandates no duplication. Extract to a shared scripts/lib/link_utils.py and import from both.

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🟡 Should-Fix (4)

[A-3] Fragment not stripped before os.path.normpath() in rewrite_links_for_pi
doc.md#section is passed whole to normpath, which will mangle #section/subsection on Windows. Split the fragment before normalization, re-append after: path, frag = target.split('#', 1) if '#' in target else (target, '')

[A-4] Windows machine-path regex off-by-one
r"[A-Z]:\\\\Users" in a raw string is two literal backslashes (C:\\Users). Real Windows paths use a single backslash. Fix: r"[A-Z]:\\Users"

[B-2] No unit tests for rewrite_links_for_pi()
check-skill-links.py is an integration gate only — it cannot catch rewriter regressions on image links ![](), nested parens in URLs, or fragment-only links. Add tests/test_srp_engine.py with unit cases for rewrite_links_for_pi.

[B-3] Undocumented exclusion of .cursor/.gemini dirs from link gate
check-skill-links.py silently skips those trees with no comment. Future maintainers will have no signal that the check should eventually cover them. Add a TODO comment with rationale.

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🔵 Consider

• body_pi_skill → pi_skill_body for more natural IR field semantics
• check() in check-skill-links.py is already pushing the 20-line function limit — extract check_file_links(smd, root) helper before it grows
• Document that inlined sibling REFERENCE.md links correctly resolve to external GitHub source (expected behavior)

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Core approach is sound and the link fixes themselves are correct. Address the items above and re-request review.

[danielvm-git]

Merged via PR #80 which resolved the dual-blind code review findings.