test(a11y): cover delayed and interrupted Map Source focus

Keep the Esri settlement assertion exact, verify selected-source focus and Tab departure in Chromium, cancel pending work during disposal, and document the focused behavior.

src/mapSourceFocus.test.mjs

@@ -230,3 +230,10 @@ test('pointer leave preserves established keyboard focus and the open tray', ()
 });
 
 
+
+test('disposed UI cannot complete a pending handoff', () => {
+  const h = harness({ hidden: true }); h.key(); h.tick();
+  h.manager._disposed = true; h.show(); h.drain();
+  assert.equal(h.document.activeElement, h.disclosure);
+  assert.equal(h.calls(), 1); assert.equal(h.timers.size, 0);
+});

src/mapStackChips.test.mjs

@@ -344,7 +344,7 @@ test('the Visual Presets tray owns Map Source and the retired left panel is abse
     'the compact wing must expose a semantic keyboard disclosure',
   );
   assert.match(ui, /event\.key !== 'Escape'[\s\S]*?disclosure\?\.focus/);
-  assert.match(ui, /map-stack-chip\.active, \.map-stack-chip/);
+  assert.match(ui, /querySelector\('\.map-stack-chip\.active'\)\s*\|\| panelEl\.querySelector\('\.map-stack-chip'\)/);
 
   assert.match(
     ui,

src/ui.js

@@ -10167,6 +10167,7 @@ export class StyleManager {
     this._globalStatusNotice = null;
     if (this._globalLoadingStatus) this._globalLoadingStatus.hidden = true;
     this._disposed = true;
+    this._cancelMapSourceFocus?.();
     // Revoke persistence/hash authority before teardown can emit manager changes.
     this._layerStateCoordinator?.destroy();
     this._layerStateCoordinator = null;