refactor(engine): ambiguity burn-down batch 2 — SettingsResource cleared, 198 → 171

New SettingsMutation set: the per-frame settings mutators
(handle_volume_keys → record_window_geometry_changes →
persist_window_geometry_after_debounce) run as a deterministic chain
ordered before GameMutation, so every reader already after GameMutation
observes the current frame's settings transitively. The four readers
outside that ordering (modal enter-speed chain, focus-ring pulse, HUD
avatar, and the game plugin's pre-mutation chain) are ordered after the
set explicitly.

SettingsResource ambiguities: 21 → 0. Baseline ratchets 198 → 171.

Refs #143

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

solitaire_engine/src/hud_plugin/mod.rs

@@ -473,7 +473,13 @@ impl Plugin for HudPlugin {
                 apply_hud_visibility.before(LayoutSystem::UpdateOnResize),
             )
             .add_systems(Update, restore_hud_on_modal)
-            .add_systems(Update, (update_hud_avatar, handle_avatar_button))
+            .add_systems(
+                Update,
+                (
+                    update_hud_avatar.after(crate::settings_plugin::SettingsMutation),
+                    handle_avatar_button,
+                ),
+            )
             .add_systems(Update, update_won_previously.after(GameMutation))
             .add_systems(Update, announce_auto_complete.after(GameMutation))
             .add_systems(