prose-pointer-lint-must-resolve-cross-skill-docs-root

When adding a lint check for prose pointers (e.g., `docs/ownership-matrix.md` references inside SKILL.md files), resolving them only relative to the skill’s own directory produces false failures for governance docs that live at the skills-root docs/ directory. The lint resolver must check both <skill-dir>/docs/<file> AND <skills-root>/docs/<file> before flagging a reference as dead.