docs: record settled L3 decision — beta title band stays textual, no channel accent

Daniel (2026-07-27): the S18 beta channel title band gets no distinct
visual accent; L3 restyles it in the standard B pastel palette and the
beta-vs-stable distinction stays purely textual. Closes the one open fork
from the L3 readiness review.

PLAN.md

@@ -453,8 +453,11 @@ feature work runs in parallel, ungated by Phase L.
   rework). (4) The phase-s branch carries an **older L1 kit** (its `action_bar` predates dev's
   L4–L7 `theme` palette revisions) — after Phase S merges, L3 draws against dev's current
   `theme`/`draw_kit`, so re-confirm the palette roles L3 consumes are dev's, not the branch's
-  stale copy. **One genuine open question for Daniel** (see the assessment) — otherwise the
-  settled DS-1/2/3 spec forces the rest.
+  stale copy. **The single open question is now RESOLVED (Daniel, 2026-07-27):** the S18 beta
+  channel title band gets **no distinct visual accent** — L3 restyles the title band in the
+  standard B pastel palette, and the beta-vs-stable distinction stays **purely textual** (the
+  channel-derived plugin name, as today), no channel-specific accent color. With that closed,
+  the settled DS-1/2/3 spec forces the rest.
 
 ---
 

docs/product/visual-design-language.md

@@ -633,6 +633,15 @@ not forecast:
   against **dev's** current `theme`/`draw_kit`, so the restyle consumes dev's pastel-on-grey
   roles, not the branch's stale copy — a merge-hygiene note, not a scope change.
 
+**Settled: the beta channel title band gets no distinct visual accent (Daniel,
+2026-07-27).** L3 restyles the title band in the standard B pastel palette, the same as the
+stable channel. The beta-vs-stable distinction stays **purely textual** — the channel-derived
+plugin name (as today, via `app_version`) is the only signal; there is **no** channel-specific
+accent color. Reasoning: one look across channels keeps the kit palette single-sourced and
+avoids a per-channel branch in the restyle; the textual name already disambiguates. This
+closes the one open fork the L3 readiness review surfaced (see PLAN.md §Phase L, L3
+must-verify).
+
 **Coordination contract (stated once, load-bearing).** Phase S's editor/embed UX build
 their interaction UX with the *current* drawing and **adopt the L1 kit when it is available —
 they are not gated on Phase L.** Whichever lands first (L1 kit or the Phase S UX), the kit is