developing-reef

# Developing Reef Use this skill as the project onboarding guide for non-test Reef changes. The workspace contains a renderer-neutral Rust app engine plus the Reef TUI frontend. Every host must stay responsive, and expensive work must not run from a renderer. ## Core Architecture Rules - Keep `ui::*::render` on cached state only. Do not call git, filesystem walks, diff generation, syntax highlighting, external processes, or long formatting from render. Renderer-specific media geometry may be cached during render; decoder open/rebuild work starts from the host tick. - Treat input handlers as intent dispatchers. They decode terminal input and dispatch `reef_app::AppCommand`; they must not directly own business state or do blocking host work. - Route expensive work through `reef-app`'s task coordinator; merge worker results from `ReefApp::step`. - Put UI-independent logic in `crates/reef-core`; shared host filesystem services such as the unified preference store belong in `crates/reef-io`; keep ratatui/crossterm rendering and input orchestration in `crates/reef-tui`. - Put renderer-neutral app state, async scheduling, worker-result merge, settings state, nav/history, preview/search/git/graph orchestration in `crates/reef-app`. - Renderer hosts dispatch preview definition requests with a typed source cursor and viewport budget. For local backends, `reef-app` marks the initial workspace index stale and schedules its build from `step`; remote backends keep that unsupported wor...