Add cheatsheet-pdf plugin

[wesnick]

What

Adds a new cheatsheet-pdf plugin: renders a Markdown document into a compact, print-ready PDF cheatsheet — a dense single-page (or single-sheet, two-sided) reference — via pandoc → HTML → headless Chromium.

It grew out of a real task (turning a tool cheatsheet into a one-page printable PDF), generalized into a reusable, evals-backed skill.

Why it's more than a wrapper

The headline feature is auto-fit: instead of hand-tuning font sizes until content fits, build_cheatsheet.py binary-searches the largest uniform zoom whose render still respects --max-pages (default 1). The result fills the sheet as much as possible without spilling — the same outcome as manual tuning, found in ~7 renders.

The SKILL.md teaches the two non-obvious layout traps as durable knowledge (per the "explain WHY" bar in AGENTS.md):

• table-layout: fixed — without it a wide table sizes past its column and paints over the neighbouring column (text-on-text overlap).
• Title outside the column flow — a column-spanning title element corrupts downstream layout positions; rendering it as a full-width banner above .cols avoids that.

Contents

plugins/cheatsheet-pdf/
├── .claude-plugin/plugin.json
├── package.json
├── README.md
└── skills/cheatsheet-pdf/
    ├── SKILL.md
    ├── assets/cheatsheet.css        # the print stylesheet (the look)
    └── scripts/build_cheatsheet.py  # stdlib-only, uv run

Plus standard registration: .codex/skills/cheatsheet-pdf sidecar symlink, marketplace.json entry, root README catalog row (new Documents category), CODEOWNERS, and a 4-case eval suite in evals/cases/cheatsheet-pdf/ (positive / two-sided / negative-longform / edge-overlap).

Requirements

External tools on PATH (not packages): pandoc and a Chromium browser (google-chrome, chromium, …). The script is stdlib-only and names no harness-specific tools — runs the same under Claude Code, Codex, and pi.

Verification

• just validate — plugin metadata, frontmatter, codex sidecar: all in sync
• just lint — ruff check + ruff format --check: clean
• just stats — 6/6 skills have eval coverage; cheatsheet-pdf: 4 cases
• End-to-end run against a real cheatsheet: 1 page at zoom 1.004 ✓

PR checklist

• Valid frontmatter; kebab-case name matches directory
• ## When to Use / ## When NOT to Use present
• Anti-patterns documented with reasoning
• positive + negative + edge eval cases
• README harness-support section
• Registered in marketplace.json, README, CODEOWNERS
• Codex sidecar symlink
• No hardcoded absolute paths

🤖 Generated with Claude Code