- Arrow keys only walk the colours on screen: the Document tab's search
results, and the Color books matches while searching (the whole book,
page after page, otherwise). One helper per tab now gives the visible
colours to both the view and the arrow keys.
- show_identity no longer returns an unused bool; ink() absorbs its
one-use ink_is_dark helper.
- document::layer_identity joins a layer's book and colour name, used by
the Document scan and the panel's current colour instead of two copies.
- Recently-used sorting looks a colour's rank up once (sort_by_cached_key)
instead of on every comparison.
- Searching compares case-insensitively without allocating a lower-case
copy of every name on each redraw (ASCII queries).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013rGmDUNr1hUf4zo1X3dak8