diff --git a/client/scripts/eslint-baseline.json b/client/scripts/eslint-baseline.json
index ea5a7bcfd..2c957d88d 100644
--- a/client/scripts/eslint-baseline.json
+++ b/client/scripts/eslint-baseline.json
@@ -1,6 +1,6 @@
 {
   "src": {
-    "@typescript-eslint/no-non-null-assertion": 385,
+    "@typescript-eslint/no-non-null-assertion": 384,
     "@typescript-eslint/no-misused-promises": 849,
     "no-console": 88,
     "complexity": 222,
diff --git a/client/src/components/Studio/StudioHeader.test.tsx b/client/src/components/Studio/StudioHeader.test.tsx
index cb6169d4b..eb2f79239 100644
--- a/client/src/components/Studio/StudioHeader.test.tsx
+++ b/client/src/components/Studio/StudioHeader.test.tsx
@@ -102,10 +102,10 @@ describe('StudioHeader', () => {
   it('FE-STUDIO-HEAD-006: auto layout offers this spread and the whole book', () => {
     const { s } = head();
     fireEvent.click(screen.getByRole('button', { name: /journey.studio.autoLayout/ }));
-    fireEvent.click(screen.getByRole('menuitem', { name: /journey.studio.relayoutSpread\b/ }));
+    fireEvent.click(screen.getByRole('menuitem', { name: /^journey\.studio\.relayoutSpread/ }));
     expect(s.relayoutCurrentSpread).toHaveBeenCalled();
     fireEvent.click(screen.getByRole('button', { name: /journey.studio.autoLayout/ }));
-    fireEvent.click(screen.getByRole('menuitem', { name: /journey.studio.relayoutBook\b/ }));
+    fireEvent.click(screen.getByRole('menuitem', { name: /^journey\.studio\.relayoutBook/ }));
     expect(s.relayoutBook).toHaveBeenCalled();
   });
 
diff --git a/client/src/components/Studio/StudioShell.tsx b/client/src/components/Studio/StudioShell.tsx
index eba329279..7a70e5267 100644
--- a/client/src/components/Studio/StudioShell.tsx
+++ b/client/src/components/Studio/StudioShell.tsx
@@ -3,6 +3,7 @@ import { createPortal } from 'react-dom'
 import { useNavigate } from 'react-router'
 import { BookOpen, Download, Maximize2, Minus, Plus } from 'lucide-react'
 import { useJourneyStudio } from '../../pages/journeyStudio/useJourneyStudio'
+import { useTranslation } from '../../i18n'
 import { foliosOf } from './bookSheets'
 import { StudioSidebar } from './StudioSidebar'
 import type { RailSection } from './sidebar/railSections'
@@ -153,6 +154,7 @@ export default function StudioShell() {
 export type Studio = ReturnType<typeof useJourneyStudio>
 
 function Workbench({ s, bookView, setBookView }: { s: Studio; bookView: boolean; setBookView: (on: boolean) => void }) {
+  const { t } = useTranslation()
   return (
     <div className="st-work-wrap">
       <div className="st-work" ref={s.workRef}>
@@ -198,8 +200,8 @@ function Workbench({ s, bookView, setBookView }: { s: Studio; bookView: boolean;
         <button type="button"
           onClick={() => setBookView(!bookView)}
           aria-pressed={bookView}
-          aria-label={s.t('journey.studio.bookView')}
-          title={s.t('journey.studio.bookView')}
+          aria-label={t('journey.studio.bookView')}
+          title={t('journey.studio.bookView')}
           className={bookView ? 'is-on' : undefined}
         >
           <BookOpen size={14} />
diff --git a/client/src/sync/glPrefetcher.ts b/client/src/sync/glPrefetcher.ts
index 2060c90ca..af1daf568 100644
--- a/client/src/sync/glPrefetcher.ts
+++ b/client/src/sync/glPrefetcher.ts
@@ -126,20 +126,26 @@ function enumerateTileUrls(bbox: TileBbox, sources: TileSource[]): string[] {
   const out: string[] = []
   for (const source of sources) {
     for (let z = Math.max(source.minZoom, VECTOR_MIN_ZOOM); z <= Math.min(source.maxZoom, VECTOR_MAX_ZOOM); z++) {
-      // Same screen-widened rectangle as the raster side: the opening fitBounds
-      // view shows more than the places extent on the non-limiting axis (#2180).
-      const { minX, maxX, minY, maxY } = tileRange(bbox, z)
-      for (let x = minX; x <= maxX; x++) {
-        for (let y = minY; y <= maxY; y++) {
-          out.push(source.template.replace('{z}', String(z)).replace('{x}', String(x)).replace('{y}', String(y)))
-          if (out.length >= MAX_VECTOR_TILES) return out
-        }
-      }
+      if (!pushZoomTiles(out, source.template, bbox, z)) return out
     }
   }
   return out
 }
 
+/** One zoom's tiles of a source onto `out`; false once the run is full. */
+function pushZoomTiles(out: string[], template: string, bbox: TileBbox, z: number): boolean {
+  // Same screen-widened rectangle as the raster side: the opening fitBounds
+  // view shows more than the places extent on the non-limiting axis (#2180).
+  const { minX, maxX, minY, maxY } = tileRange(bbox, z)
+  for (let x = minX; x <= maxX; x++) {
+    for (let y = minY; y <= maxY; y++) {
+      out.push(template.replace('{z}', String(z)).replace('{x}', String(x)).replace('{y}', String(y)))
+      if (out.length >= MAX_VECTOR_TILES) return false
+    }
+  }
+  return true
+}
+
 /**
  * The style's tiled sources, vector first. A source given as a TileJSON
  * reference gets its template and zooms from there: the tile path carries a
diff --git a/client/tests/unit/studio/studioStore.pageFull.test.tsx b/client/tests/unit/studio/studioStore.pageFull.test.tsx
index cb4c9f113..e8fd21345 100644
--- a/client/tests/unit/studio/studioStore.pageFull.test.tsx
+++ b/client/tests/unit/studio/studioStore.pageFull.test.tsx
@@ -2,6 +2,10 @@ import { act, render } from '@testing-library/react';
 import { MAX_SPREAD_ELEMENTS, type BookDocument, type BookElement, type BookSpread } from '@trek/shared';
 import { beforeEach, describe, expect, it, vi } from 'vitest';
 
+const toast = vi.hoisted(() => ({ warning: vi.fn() }));
+vi.mock('../../../src/components/shared/Toast', () => ({ useToast: () => toast }));
+vi.mock('../../../src/i18n', () => ({ useTranslation: () => ({ t: (key: string) => key }) }));
+
 import { StudioNotices } from '../../../src/components/Studio/StudioNotices';
 import { useStudioStore } from '../../../src/store/studioStore';
 
@@ -56,7 +60,7 @@ beforeEach(() => {
 describe('a full page', () => {
   it('FE-STUDIO-FULL-001: refuses one more element and counts the refusal', () => {
     expect(store().addElement(0, el('extra'))).toBe(false);
-    expect(store().doc!.spreads[0].elements).toHaveLength(MAX_SPREAD_ELEMENTS);
+    expect(store().doc?.spreads[0]?.elements).toHaveLength(MAX_SPREAD_ELEMENTS);
     expect(store().refusedFull).toBe(1);
     expect(store().addElement(1, el('fits'))).toBe(true);
     expect(store().refusedFull).toBe(1);
@@ -65,25 +69,24 @@ describe('a full page', () => {
   it('FE-STUDIO-FULL-002: a paste onto it is refused and counted', () => {
     useStudioStore.setState({ clipboard: { fromSpreadId: 'room', elements: [el('a')] } });
     store().paste(0);
-    expect(store().doc!.spreads[0].elements).toHaveLength(MAX_SPREAD_ELEMENTS);
+    expect(store().doc?.spreads[0]?.elements).toHaveLength(MAX_SPREAD_ELEMENTS);
     expect(store().refusedFull).toBe(1);
   });
 
   it('FE-STUDIO-FULL-003: a duplicate on it is refused and counted', () => {
     store().duplicate(0, ['f0']);
-    expect(store().doc!.spreads[0].elements).toHaveLength(MAX_SPREAD_ELEMENTS);
+    expect(store().doc?.spreads[0]?.elements).toHaveLength(MAX_SPREAD_ELEMENTS);
     expect(store().refusedFull).toBe(1);
   });
 
   it('FE-STUDIO-FULL-004: the Studio says it once per refusal', () => {
-    const addToast = vi.fn();
-    window.__addToast = addToast;
+    toast.warning.mockClear();
     render(<StudioNotices />);
-    expect(addToast).not.toHaveBeenCalled();
+    expect(toast.warning).not.toHaveBeenCalled();
     act(() => store().refuseFull());
-    expect(addToast).toHaveBeenCalledTimes(1);
-    expect(addToast.mock.calls[0][1]).toBe('warning');
+    expect(toast.warning).toHaveBeenCalledTimes(1);
+    expect(toast.warning).toHaveBeenLastCalledWith('journey.studio.pageFull');
     act(() => store().refuseFull());
-    expect(addToast).toHaveBeenCalledTimes(2);
+    expect(toast.warning).toHaveBeenCalledTimes(2);
   });
 });
diff --git a/client/tests/unit/sync/glPrefetcher.test.ts b/client/tests/unit/sync/glPrefetcher.test.ts
index 916823e83..2f947064e 100644
--- a/client/tests/unit/sync/glPrefetcher.test.ts
+++ b/client/tests/unit/sync/glPrefetcher.test.ts
@@ -147,7 +147,7 @@ describe('prefetchVectorForPlaces', () => {
     const zooms = new Set(
       [...cache.store.keys()]
         .filter(u => u.endsWith('.pbf') && u.includes('/planet/'))
-        .map(u => Number(u.split('/planet/')[1]!.split('/')[1])),
+        .map(u => Number((u.split('/planet/')[1] ?? '').split('/')[1])),
     );
     // z14 is the last one OpenFreeMap serves; MapLibre scales it beyond that
     // rather than asking for another, which is why this stops where raster could not.
@@ -166,7 +166,7 @@ describe('prefetchVectorForPlaces', () => {
 
     const xs = [...cache.store.keys()]
       .filter(u => u.endsWith('.pbf') && u.includes('/planet/'))
-      .map(u => u.split('/planet/')[1]!.split('/'))
+      .map(u => (u.split('/planet/')[1] ?? '').split('/'))
       .filter(parts => Number(parts[1]) === 7)
       .map(parts => Number(parts[2]));
     expect((Math.max(...xs) - Math.min(...xs) + 1) * 256).toBeGreaterThanOrEqual(window.innerWidth);
@@ -233,9 +233,9 @@ describe('a style with a raster source ahead of the vector one', () => {
     const result = await prefetchVectorForPlaces(places, STYLE_URL);
     expect(result.template).toBe(TILE_TEMPLATE);
     const urls = requested.map(r => r.url);
-    const vectorZooms = new Set(urls.filter(u => u.includes('/planet/')).map(u => Number(u.split('/planet/')[1]!.split('/')[1])));
+    const vectorZooms = new Set(urls.filter(u => u.includes('/planet/')).map(u => Number((u.split('/planet/')[1] ?? '').split('/')[1])));
     expect(Math.max(...vectorZooms)).toBe(14);
-    const reliefZooms = urls.filter(u => u.includes('/ne2sr/')).map(u => Number(u.split('/ne2sr/')[1]!.split('/')[0]));
+    const reliefZooms = urls.filter(u => u.includes('/ne2sr/')).map(u => Number((u.split('/ne2sr/')[1] ?? '').split('/')[0]));
     expect(reliefZooms.length).toBeGreaterThan(0);
     expect(Math.max(...reliefZooms)).toBe(6);
   });