fix: harden and de-slop the merged sidebar/chat/settings batch

Post-merge follow-ups for #2740 #2735 #2734 #2690 #2676 #2738 #2684
#2689 #2733 #2739 #2462 #2687 #2736 #2618 #2697, plus three regressions
found while reviewing them:

- ctrl/cmd+digit while typing no longer switches session tabs (#2503 was
  still open in practice: the guard only covered the mod+alt surface binding)
- Shiki template-call sanitizer now covers every bundled grammar, including
  the js/ts aliases and embedding grammars; timed-out highlight requests are
  memoized and no longer cancel unrelated in-flight requests
- settings flush on suspend uses keepalive and also fires on Capacitor
  appStateChange; keeps the selected model persisted across mode switches
- remote-only branches fetch before checkout; range helpers fail clearly
- git status invalidation now fires for runtime adapters too
- settings number inputs and select triggers size in ch so they scale with
  the interface font
- recent-activity timestamps tick from one list-level ticker
- Markdown preview find goes through the shared find_in_file keybind with
  containment, no longer counts its own bar, and debounces observer runs
- #2676 reverted; #2524 fixed by fading the sticky header's own background
  instead of overlaying the content below it
- sticky group headers in the model picker and sidebar render again
  (oc-sticky-fade-scroller class restored after 9b9d7069c)
- project switcher names are left-aligned again (wrapper lost in 26dbc2f30)
- tool card quick-open icon is always visible and opens the same line as the
  expanded card's button
- tautological tests replaced or removed; new oxlint findings fixed

packages/ui/src/lib/vscodeBootstrap.test.ts

@@ -1,18 +1,35 @@
 import { afterEach, describe, expect, test } from 'bun:test';
 import { getVSCodeBootstrapConfig, isVSCodeBootstrapPresent } from './vscodeBootstrap';
 
+interface TestWindow {
+  __VSCODE_CONFIG__?: { workspaceFolder: string; workspaceFolders: { name: string; path: string }[] };
+}
+
+/**
+ * bun test runs without a DOM, so `globalThis` has no `window` binding to
+ * assign through. Defining the property directly installs the stub without
+ * asserting that it is a real `Window`.
+ */
+const setTestWindow = (value: TestWindow | undefined): void => {
+  if (value === undefined) {
+    Reflect.deleteProperty(globalThis, 'window');
+    return;
+  }
+  Object.defineProperty(globalThis, 'window', { value, configurable: true, writable: true });
+};
+
 describe('VS Code bootstrap config', () => {
   afterEach(() => {
-    delete (globalThis as { window?: unknown }).window;
+    setTestWindow(undefined);
   });
 
   test('reads extension-host __VSCODE_CONFIG__ before RuntimeAPIs exist', () => {
-    (globalThis as { window: unknown }).window = {
+    setTestWindow({
       __VSCODE_CONFIG__: {
         workspaceFolder: '/workspace/project-one',
         workspaceFolders: [{ name: 'project-one', path: '/workspace/project-one' }],
       },
-    };
+    });
 
     expect(getVSCodeBootstrapConfig()).toEqual({
       workspaceFolder: '/workspace/project-one',