LabScriven: Release notes that read like a human wrote them

Scriven turns your Conventional-Commits history into clean, grouped Markdown release notes through a pure, tested parsing and grouping pipeline. The interesting part is the optional --narrate layer: it rewrites the notes with Claude when a key is available, and gracefully falls back to an offline summary when there isn't one, so the core tool never depends on the network. It is a from-scratch CLI with zero dependencies that you can download and run locally.