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/pi-upstreams.tsx

@@ -84,7 +84,7 @@ export function PiUpstreamsBlock() {
             key: "model",
             header: "模型",
             hideBelow: "sm",
-            cell: (r) => <code className="text-meta break-all">{r.defaultModel ?? "provider 默认"}</code>,
+            cell: (r) => <code className="text-meta break-all">{r.defaultModel ?? "默认模型"}</code>,
           },
           { key: "status", header: "状态", cell: (r) => <UpstreamStatusBadge u={r} /> },
         ]}
@@ -159,7 +159,7 @@ function UpstreamDrawer({
     try {
       await update.mutateAsync({ id: upstream.id, body: parsed.data });
       setV((s) => ({ ...s, apiKey: "" }));
-      toast.success(`${v.name.trim()}已保存`);
+      toast.success(`${v.name.trim()} 已保存`);
     } catch (err) {
       toast.error(errorMessage(err, "保存失败"));
     }