test(assets): add E2E tests for media type filter

Add cloud-only (@cloud) Playwright tests for the media type filter
checkboxes in the assets sidebar. Tests cover: filter menu visibility
with all four media type options, filtering to show only one type,
and re-enabling a filter to restore all assets.

Fixes #10780

browser_tests/fixtures/components/SidebarTab.ts

@@ -207,6 +207,14 @@ export class AssetsSidebarTab extends SidebarTab {
     return this.page.getByRole('button', { name: 'View settings' })
   }
 
+  get filterButton() {
+    return this.page.getByRole('button', { name: 'Filter by' })
+  }
+
+  filterCheckbox(label: string) {
+    return this.page.getByRole('checkbox', { name: label })
+  }
+
   // --- View mode ---
 
   get listViewOption() {
@@ -347,6 +355,16 @@ export class AssetsSidebarTab extends SidebarTab {
       .waitFor({ state: 'visible', timeout: 3000 })
   }
 
+  async openFilterMenu() {
+    await this.dismissToasts()
+    await this.filterButton.click()
+    // Wait for popover content with checkboxes to render
+    await this.filterCheckbox('Image').waitFor({
+      state: 'visible',
+      timeout: 3000
+    })
+  }
+
   async rightClickAsset(name: string) {
     const card = this.getAssetCardByName(name)
     await card.click({ button: 'right' })