Implementation Plan: Calm workspace shell

Technical context

Rust 2021, GTK4/libadwaita, existing resource stylesheet. Presentation only; no new dependencies, IPC, persistence or core types. Existing ADRs apply.

Constitution check

Spec and clarified assumptions precede implementation. Write a native display regression for empty-state actions and narrow geometry before changing code. Retain the existing shell/navigation/approval tests for structural invariants. Full verification and light/dark evidence are mandatory.

Design

Follow research.md and exploration.html. Edit style.css in its existing sections: quiet progress badges, a neutral inset selection marker, flat header tools with explicit checked/pressed states, one terminal shadow across focus/attention rules. Use StatusPage copy and GTK-formatted shortcut labels below existing primary buttons in app.rs. No custom widget, motion, font, bitmap asset or navigation state.

Verification

Extend existing native scenes with empty-state capture at desktop and 360px, light/dark and Sans 18/high contrast. Assert action names and shortcut accelerators, then exercise keyboard/button activation through existing action tests. Compare populated screenshots to baseline. Run scripts/verify.sh full and ask a second reviewer for docs/17 visual rubric review. Save selected evidence and proof limits.