fix(web): visual QA front-end items U4–U6, U13–U16 and copy list

- U4: form save failures toast the first problem and scroll/focus the first
  invalid field (policy draft, settings cards, resource drawers, subscription
  form) via lib/form-errors.
- U5: FormField keeps 8px between a hint and the next label.
- U6: file manager status bar keeps free space left-aligned, clear of the
  Agent button.
- U13: move/copy dialog stops "target is the source folder / inside the
  source" before requesting a preview (transferTargetProblem + tests).
- U14: account popover uses the solid float material.
- U15/U16: inbox tile hint shortened; TMDB assign dialog uses the shared
  Select and labelled fields (type, TMDB ID, note).
- Copy: "TMDB 已保存" spacing, API Key block no longer repeats the section
  title, whole-day intervals read "每 7 天", "最高级别:提示",
  "延后:已有计划在途", failed records show "未生成目标路径", upstream model
  column "默认模型".

Co-Authored-By: Claude Opus 5.5 <[email protected]>

apps/web/app/components/settings/api-keys.tsx

@@ -104,8 +104,8 @@ export function ApiKeysSection() {
     <SettingsBlock
       section="api-keys"
       anchor="keys"
-      title="API Key"
-      description="签发给外部程序(媒体服务器插件、脚本)的 Key,按权限范围授权。本机 Token 在「账户与安全」。"
+      title="已签发的 Key"
+      description="给媒体服务器插件、脚本等外部程序用,按权限范围授权。本机 Token 在「账户与安全」。"
       plain
       actions={
         <Button size="sm" onClick={() => setOpen(true)}>