feat(responsive): mobile polish — topbar, drawer, footer, tabs, notification dropdown

Unifies the breakpoint system and fixes cross-layer CSS bugs that kept
the old mobile hide rules from ever taking effect.

Breakpoints:
- Document canonical xs/sm/md/lg/xl/2xl scale in variables.base.css
- Replace 968px one-offs with 1024px (app-details, app-page-editor)
- Make details tab-panel max-width responsive (min(70ch, 100%))

Topbar (< md):
- Hide breadcrumb in components layer so cross-layer overrides actually win
- Dock search icon alongside right-column icons via flex layout
- Add xs (400px) tightening for hit-area preservation
- Hide brand divider alongside hidden brand name
- Switch hover states to theme-aware --app-dropdown-hover-background-color

Mobile drawer:
- Icon-bar now vertical like desktop (was horizontal top strip, effectively invisible)
- Sidebar shifted 52px right so icon-bar and sidebar slide in as one 280px unit
- Add breathing room above first nav item (20px top padding)

List tabs:
- Rewrite .app-list-tabs to horizontal scroll with hidden scrollbar, snap,
  and mask-image gradient fades; add initListTabs to scroll active into view
- Register as runtime component in app-init.js

List toolbar:
- Stack wide controls (multi-select, search/text inputs) full-width below sm,
  keep compact controls at natural width

Footer:
- New dedicated app-footer.css with mobile-first stacking, border-top separator,
  theme-aware hover; remove redundant rules from app-shell.css

Notification dropdown:
- Width with min(360px, 100vw - 2rem) and min-width: 0 override global
  details > ul rule; switch to position: fixed below md so it hugs the
  viewport right edge instead of the non-rightmost bell button

Content spacing:
- Add padding-block-start to .app-main-content on mobile (was 0)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

web/js/app-init.js

@@ -6,6 +6,7 @@ import { initPasswordHints } from './components/app-password-hints.js';
 import { initBadgeCopy } from './components/app-copy-badge.js';
 import { initCopyField } from './components/app-copy-field.js';
 import { initMultiSelectComponent } from './components/app-multiselect-init.js';
+import { initTokenSelect } from './components/app-token-select.js';
 import { initSidebarToggle } from './components/app-toggle-sidebar.js';
 import { initAsidePanels } from './components/app-toggle-aside-panels.js';
 import { initDetailsAsideToggle } from './components/app-toggle-details-aside.js';
@@ -22,6 +23,7 @@ import { initTelemetrySettings } from './components/app-settings-telemetry.js';
 import { initStandardDetailPages } from './components/app-standard-detail-page.js';
 import { initAutoSubmit } from './components/app-auto-submit.js';
 import { initTabs } from './components/app-tabs.js';
+import { initListTabs } from './components/app-list-tabs.js';
 import { initSessionWarning } from './components/app-session-warning.js';
 import { initFsLightboxRefresh } from './components/app-fslightbox-refresh.js';
 import { initFileUpload } from './components/app-file-upload.js';
@@ -182,6 +184,10 @@ const bootRuntime = async () => {
     scope: 'global',
     configPath: 'components.multiSelect',
   });
+  runtime.register('token-select', initTokenSelect, {
+    selector: '[data-app-component="token-select"]',
+    configPath: 'components.tokenSelect',
+  });
   runtime.register('details-state', initDetailsState, {
     scope: 'global',
     configPath: 'components.detailsState',
@@ -265,6 +271,13 @@ const bootRuntime = async () => {
       storageVersion: 'v1',
     },
   });
+  runtime.register('list-tabs', initListTabs, {
+    selector: '.app-list-tabs',
+    configPath: 'components.listTabs',
+    defaultConfig: {
+      selector: '.app-list-tabs',
+    },
+  });
   runtime.register('session-warning', initSessionWarning, {
     selector: '[data-app-component="session-warning"]',
     configPath: 'components.sessionWarning',