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/files/model.ts

@@ -178,6 +178,23 @@ export function parentRel(path: string): string {
   return i < 0 ? "" : path.slice(0, i);
 }
 
+/**
+ * 移动 / 复制目标的前端预检(与服务端 transfer 校验同口径,QA U13):目标就是源所在目录,
+ * 或目标在源目录之内时直接提示,不发预览请求。
+ */
+export function transferTargetProblem(
+  items: { root: string; path: string }[],
+  target: { root: string; path: string },
+): string | null {
+  for (const it of items) {
+    if (it.root !== target.root) continue;
+    if (target.path === it.path || target.path.startsWith(`${it.path}/`))
+      return `目标在源目录之内(${baseName(it.path)}),换一个目录`;
+    if (parentRel(it.path) === target.path) return `${baseName(it.path)} 已在这个目录里,换一个目录`;
+  }
+  return null;
+}
+
 export function baseName(path: string): string {
   const i = path.lastIndexOf("/");
   return i < 0 ? path : path.slice(i + 1);