feat: multi-material overlays, presentation guides, and release prebuilds

Align control/presentation with presentation screen rect and darkness z-order; sync window titles and session window cleanup. Pack Win/Mac/Linux with npmRebuild disabled and release-native-prep for classic-level and sharp.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/renderer/materials/MaterialsApp.tsx

@@ -59,7 +59,7 @@ export function MaterialsApp() {
   useEffect(() => {
     const onKey = (e: KeyboardEvent) => {
       if (e.key === 'Escape') {
-        if (overlay?.activeMaterialId) {
+        if ((overlay?.activeMaterialIds?.length ?? 0) > 0) {
           void overlayApi.dispatch({ kind: 'hide' });
           return;
         }
@@ -72,10 +72,10 @@ export function MaterialsApp() {
     };
     window.addEventListener('keydown', onKey);
     return () => window.removeEventListener('keydown', onKey);
-  }, [overlay?.activeMaterialId, overlay?.zoomTool, overlayApi]);
+  }, [overlay?.activeMaterialIds, overlay?.zoomTool, overlayApi]);
 
   const materials = session?.project?.materials ?? [];
-  const activeId = overlay?.activeMaterialId ?? null;
+  const activeIds = overlay?.activeMaterialIds ?? [];
   const zoomTool = overlay?.zoomTool ?? null;
 
   return (
@@ -88,7 +88,7 @@ export function MaterialsApp() {
         materials={materials}
         selectedId={selectedId}
         onSelect={onSelect}
-        activeMaterialId={activeId}
+        activeMaterialIds={activeIds}
         onTileActivate={(id) => {
           const mat = materials.find((m) => m.id === id);
           void overlayApi.dispatch({
@@ -99,7 +99,7 @@ export function MaterialsApp() {
         }}
         toolbar={
           <>
-            <div className={matStyles.browserToolbarRow}>
+            <div className={matStyles.browserToolbarZoomRow}>
               <Button
                 variant={zoomTool === 'zoomIn' ? 'primary' : 'ghost'}
                 iconOnly
@@ -131,17 +131,19 @@ export function MaterialsApp() {
                 <ZoomOutIcon />
               </Button>
             </div>
-            {activeId ? (
-              <Button
-                title={t('materials.closeOverlay')}
-                ariaLabel={t('materials.closeOverlay')}
-                tooltipPlacement="bottom"
-                onClick={() => {
-                  void overlayApi.dispatch({ kind: 'hide' });
-                }}
-              >
-                {t('materials.closeOverlay')}
-              </Button>
+            {activeIds.length > 0 ? (
+              <div className={matStyles.browserToolbarFullBtn}>
+                <Button
+                  title={t('materials.closeOverlay')}
+                  ariaLabel={t('materials.closeOverlay')}
+                  tooltipPlacement="bottom"
+                  onClick={() => {
+                    void overlayApi.dispatch({ kind: 'hide' });
+                  }}
+                >
+                  {t('materials.closeOverlay')}
+                </Button>
+              </div>
             ) : null}
             <div className={matStyles.browserToolbarHint}>
               {zoomTool === 'zoomIn'