refactor(engine): ambiguity burn-down batch 3 — board paint chain, 171 → 47

The Sprite/Transform cluster (112 pairs) was every board painter
racing every other one. Two structural moves:

- BoardVisuals set (card_plugin): all card/marker painters run as ONE
  deterministic chain in data-flow order — layout refinement → card
  authority (sync_cards_on_change) → flip anims → shadows → highlights
  → stock indicators → resize snapping → corner labels — with
  LayoutSystem::UpdateOnResize ordered before the whole set and the
  table plugin's marker painters chained after it. Paint order is now
  identical every frame instead of scheduler-dependent.

- UiTextFx set (ui_theme): chrome text effects (score pulse/floater,
  streak flourish, modal enter, focus-ring pulse) animate Transform on
  UI entities only; they are declared ambiguous with BoardVisuals and
  with each other — the entity domains are disjoint by construction.

All chain members are cheap and change-gated; sequential execution is
not a measurable cost for a card game. Existing ordering constraints
(fan-frac before sync, shadows after sync, snap after collect) are
preserved inside the chain.

Baseline ratchets 171 → 47. Remaining: long tail of small subjects
(input, event writers, AutoCompleteState, HudVisibility).

Refs #143

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

solitaire_engine/src/ui_theme.rs

@@ -698,3 +698,12 @@ mod tests {
         assert_eq!(scaled_duration(0.18, AnimSpeed::Instant), 0.0);
     }
 }
+
+/// System set for text/UI visual effects that animate `Transform`/`Sprite`
+/// on chrome entities (HUD score pulse, streak flourish, modal enter, focus
+/// ring). These never touch board entities, so members are declared
+/// `.ambiguous_with(BoardVisuals)` and `.ambiguous_with(UiTextFx)` — the
+/// entity domains are disjoint by construction and relative order within a
+/// frame is invisible (#143).
+#[derive(bevy::ecs::schedule::SystemSet, Debug, Clone, PartialEq, Eq, Hash)]
+pub struct UiTextFx;