[ssbushi]

Follow-up to #44.

Adds zero-dependency Python 3 stdlib tooling to keep reference Tables of Contents and skill markdown files in sync before downstream import:

• scripts/sync_tocs.py: regenerates - [Title](#anchor): Lines start-end entries on skills/*/references/*.md files over 100 lines (and removes them when files shrink to 100 lines or fewer), skips CommonMark fenced code blocks, and checks fence balance, Caution: LeakR keywords, and SKILL.md frontmatter (name, description <= 1024 UTF-8 bytes).
• .githooks/pre-commit: runs python3 scripts/sync_tocs.py --staged to update and restage drifted reference TOCs on commit (enable locally with git config core.hooksPath .githooks).
• .github/workflows/validate-skills.yml and scripts/test_sync_tocs.py: runs hermetic unittest coverage and python3 scripts/sync_tocs.py --check on pushes and pull requests to main.

[gemini-code-assist]

Code Review

This pull request introduces a pre-commit hook and a Python script (sync_tocs.py) with accompanying unit tests to deterministically generate Table of Contents (TOC) and validate markdown hygiene for skills. The reviewer feedback highlights several key areas for improvement, including fixing a YAML parsing bug with empty lines in block scalars, preventing false positives in the Caution: keyword check by ignoring fenced code blocks, handling OSError when executing git commands, ensuring cross-platform path consistency on Windows using .as_posix(), and removing a non-hermetic unit test that checks the active workspace.