Portfolio polish: document dev-kit as reusable release hygiene tooling

[keepithandy]

Goal

Make dev-kit easier to understand as a reusable developer-tool project, not just a support repo for DungeonDex.

Proposed work

• Add a short public-facing explanation of what dev-kit audits.
• Add example output or a sample report file.
• Explain why the tooling is read-only by default.
• Document how dev-kit supports multiple repos over time.

Acceptance checks

• README clearly explains the tool in plain language.
• Commands are easy to copy.
• A visitor can understand how dev-kit supports the broader portfolio.
• Tests remain documented.

Guardrails

Keep the scope focused on audit/report/release hygiene. Avoid turning this into a giant automation framework too early.