feat(web): 新增控制台布局切换并完善状态与磁盘交互

新增经典、悬浮和侧栏布局，保存用户偏好，并调整工具栏、状态摘要及窄屏交互。
统一控制台弹层外观、焦点行为和中英文文案。
根据虚拟磁盘文件访问能力显示浏览入口、容量信息和不可用状态。

验证：npm run build 通过（vue-tsc 类型检查和 Vite 生产构建）。

web/src/composables/useConsoleAppearance.ts

@@ -0,0 +1,22 @@
+import { inject, provide, type InjectionKey, type Ref } from 'vue'
+import type { ConsoleLayout } from '@/composables/useConsoleLayout'
+
+// Injection follows component ownership through portals, without styling settings/login.
+const consoleAppearanceKey: InjectionKey<Readonly<Ref<ConsoleLayout>>> = Symbol('consoleAppearance')
+
+export function provideConsoleAppearance(layout: Readonly<Ref<ConsoleLayout>>) {
+  provide(consoleAppearanceKey, layout)
+}
+
+export function useConsoleAppearance() {
+  return inject(consoleAppearanceKey, undefined)
+}
+
+// Focus the panel itself so the first help tooltip does not obscure its controls on open.
+// Keyboard users can then Tab into the panel's controls in their normal order.
+export function focusConsolePanel(event: Event) {
+  if (event.target instanceof HTMLElement) {
+    event.preventDefault()
+    event.target.focus({ preventScroll: true })
+  }
+}