chore(todo): close the color-grouping research task; file the hint override

The two color-sorting reviews resolved the warm-color grouping problem; LCCL is implemented (04b82bbe). The only remaining piece, a per-hex family-hint override for the irreducible ramp-collision case, is filed as its own task.

1 files changed, 6 insertions, 2 deletions

diff --git a/todo.org b/todo.org
index 327fc531..ea53d9f8 100644
--- a/todo.org
+++ b/todo.org
@@ -109,8 +109,12 @@ Phase 5 (commit =9daeff15=). Editing a family base recolors the whole family (sh
 *** 2026-06-10 Wed @ 01:17:45 -0500 Warnings, seeding, export, README close-out landed
 Phase 6 (commit =c175e2be=). Export stays a flat palette and import needs no reconstruction (#roundtriptest: export→import→export byte-identical). =seedPkgmap= reads the flat palette unchanged. The too-similar warning stays on the full palette — the planned ramp-step exemption was dropped after analysis: ramp steps are a stepL apart (well above the ΔE threshold) so they never warn, and exempting same-family pairs would hide genuine near-duplicates (caught by #deltatest). README documents families, the ground strip, the count control/regenerate, removed-step references, and the ramp-panel removal.
 
-** TODO [#B] Color-family grouping for hue-adjacent warm colors :feature:theme-studio:research:
-The hue-anchor + lightness-scaled-threshold grouping (shipped in color families) fixed the neutrals and pale tints but can't cleanly separate hue-adjacent warm colors: this palette's olive-greens (~110-120° OKLCH) sit right on the golds (~85-95°), so by hue they merge, and a ramp that drifts in hue can split across an anchor boundary. The problem, the four approaches tried, why each failed, and directions to research (2D chromaticity clustering, lightness-aware hue grouping, ramp detection, perceptual color-naming models, an optional hex-derived family hint) are written up in =~/color-sorting.org=. Craig is finding someone to comment. Pick the work back up from that doc.
+** DONE [#B] Color-family grouping for hue-adjacent warm colors :feature:theme-studio:research:
+CLOSED: [2026-06-10 Wed]
+Resolved by two independent reviews of =~/color-sorting.org= (=~/color-sorting-codex.org=, =~/color-sorting-fable.org=, Fable's harness at =~/working/color-sorting-fable/=). Both converged on lightness-conditioned complete-linkage clustering + a floored neutral threshold; implemented in commit =04b82bbe= (replacing the hue anchors). Measured F1 0.63→0.96 on the real palette: gold and olive separate, red/blue ramps stay whole, intense-red isolates, all grays/steels consolidate, and the gray+1/gray+2/white neutral-leak bugs are fixed. The only residual (pale yellow+2 lands on the olive ramp) is geometrically irreducible from the hex — see the hint-override task below.
+
+** TODO [#C] Color-family per-hex hint override :feature:theme-studio:
+For the ~1 color per palette that sits on a ramp-collision point (e.g. yellow+2 on the distinguished palette, which by every hex signal belongs to the olive ramp though its name says gold), automatic grouping cannot recover the designer's intent. Add a per-hex family override: drag a swatch to a different column, store the override keyed by hex (never the name, so renaming is still free), consult it after the LCCL clustering, and drop/mark-stale it when the hex changes substantially. Export stays mostly flat; only overrides are extra metadata. Both reviews recommend this exact shape; details in =~/color-sorting-fable.org= (§ "The irreducible case") and =~/color-sorting-codex.org= (§ "What to store").
 
 ** 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.