docs(theme-studio): fold Codex review into palette-ramps spec

Resolved both open decisions. The contrast target is WCAG AA by default, with AAA selectable and APCA shown as a diagnostic only. The v1 foreground set is the distinct syntax-assignment hexes plus the default foreground, with locked background-only roles excluded.

Pinned what the review flagged as underspecified: a closed five-face covered set (region, hl-line, highlight, lazy-highlight, isearch), ramp defaults and palette-insertion rules (n/stepL/chromaEase, naming, collisions, clamp display), and explicit-state structured-error contracts for ramp, fgSetFor, floor, and lMax. Package and non-overlay UI cells stay single-pair in v1.

Closed the v1 face set rather than keeping the review's open-ended "any face the buffer renders text over" clause, since an open set reintroduces the gap the foreground-set decision exists to close. Kept throwing for genuine programmer error while returning structured results for bad user input, matching colormath.js.

The spec is implementation-ready. The six implementation tasks get created once Craig confirms the go. Review file consumed and deleted.

1 files changed, 1 insertions, 1 deletions

diff --git a/todo.org b/todo.org
index d0920ea8..0544f09a 100644
--- a/todo.org
+++ b/todo.org
@@ -73,7 +73,7 @@ Two features it enables (both worth building):
 
 Open design problem to address in the explainer + the ramp feature: a background-over-text effect (highlight/region/isearch/hl-line) must stay readable for EVERY foreground that can appear on it — i.e. the worst-case (lowest) contrast across the whole set of element fg colors, not a single pair. The usable background lightness is therefore capped by the darkest/closest fg in that set.
 
-The v1 feature (ramp generation + background-contrast safety, with the worst-case-floor UX) is designed in [[file:docs/theme-studio-palette-ramps-spec.org][docs/theme-studio-palette-ramps-spec.org]]; build tasks come from spec-review of that spec. Harmonic fill (feature 2) stays vNext. This task is the explainer doc itself (=docs/design/theme-studio-color-harmony.org=, the methodology).
+The v1 feature (ramp generation + background-contrast safety, with the worst-case-floor UX) is designed in [[file:docs/theme-studio-palette-ramps-spec.org][docs/theme-studio-palette-ramps-spec.org]]. Codex review incorporated 2026-06-09: both open decisions resolved (WCAG AA default target; v1 foreground set = distinct syntax hexes + default fg), v1 covered faces closed to region/hl-line/highlight/lazy-highlight/isearch, ramp defaults + function contracts pinned. Spec is implementation-ready pending Craig's go; build tasks (6 phases) get created then, per spec-response Phase 6. Harmonic fill (feature 2) stays vNext. This task is the explainer doc itself (=docs/design/theme-studio-color-harmony.org=, the methodology).
 
 ** TODO [#C] Internet radio now-playing song :feature:music:emms:
 Show the currently-playing song while streaming an internet radio station. Lives in =modules/music-config.el= (EMMS + MPV backend, M3U radio stations). The track title comes from the stream's ICY metadata — EMMS exposes it via =emms-track-description= / =emms-playing-time= and updates it on the metadata-change hook; MPV reports the ICY title too. Add an option to show the song in the minibuffer (e.g. echo on track change, or an on-demand command). Consider also a mode-line indicator as a second surface.