event-driven UI feeds, and the character window's cost lets go

- the eight heaviest UI feeds — spellbook, party, character, bags, talents, units, pet, player — rebuild only when an input moved instead of every frame: 216 → 12 µs a frame parked
- the character window's cost settles once it closes: enchant countdowns feed by the second instead of firing an inventory event into all 20 slots every frame, the paper-doll booth parks with its camera, and a window hidden under the cursor fires OnLeave so its tooltip goes with it — the reference's hover-hide law
- the walk stops paying for finished work: the loading-screen tally's per-placement walk latches off once the world is ready, the settled placement spawner is one integer compare, and billboards stop dirtying every card's transform
- never-rendering hierarchy nodes — rig anchors, joints, doodad hosts — keep the hide chain but leave the per-camera visibility sweep: 25,198 → 18,026 swept entities at Goldshire

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

crates/benilla-app/src/ui_script/extract/mod.rs

@@ -213,10 +213,18 @@ pub(super) fn drive_script(
 ) {
     let (capture, ui_cost_wanted) = run;
     let Some(mut script) = script else {
+        // No VM ⇒ no UI is sampling any booth pane. The panes map must not outlive its writer:
+        // every OTHER return in this system provably keeps pane presence unchanged (the settled
+        // gate compares the whole extracted list; the splice refuses `portrait_unit` entries),
+        // but a VM dying mid-world with the character window up would strand its pane here and
+        // the paper-doll camera would render behind a dead UI until the next full conversion.
+        booths.panes.0.clear();
         return;
     };
     let prev = prev.get(&script);
     let Ok(window) = window.single() else {
+        // Same law as the no-VM arm: no window, no sampling — a pane map with no writer lies.
+        booths.panes.0.clear();
         return;
     };
     let (w, h) = (window.width(), window.height());