fix(files): an upload is said once in any order, copy buttons speak, a link list that failed says so

- The queue holds an upload it sees land done while this tab's upload still waits for its answer, so
  the dialog's notice is the only one whichever comes first; another device's upload follows after.
- One `useCopyFeedback` for every Copy beside a value (token, share link, set-password link): Copied
  for a moment, a notice a screen reader hears, a warning when the clipboard refuses; the token
  dialog's two Copy buttons are named by what they copy.
- The share dialog's link list shows loading, and a load error with Retry, never "no links" — and no
  New link beside a list it has not seen.
- The settings texts say that signing out elsewhere or a password change revokes the API tokens.
- DESIGN.md logs the folder-link decisions; the design lab keeps only the chosen renderings of the
  Links, Tokens and Files rounds.

frontend/src/components/AccountPanel.tsx

@@ -9,13 +9,13 @@ import { displayName } from "../lib/api/account";
 import { qk } from "../lib/queryKeys";
 import { notify } from "../lib/notifications";
 import { notifyActionError } from "../lib/actionErrors";
-import { copyText } from "../lib/clipboard";
 import { formatDateTime } from "../lib/format";
 import { invalidateUserAccess } from "../lib/adminUsers";
 import type { AdminUserAccess, AdminUserRow } from "../lib/api/admin";
 import { Button } from "./ui/Button";
 import { SURFACE } from "./ui/surfaces";
 import { SectionLabel } from "./ui/Headings";
+import { useCopyFeedback } from "./useCopyFeedback";
 
 // The admin's answer to "why can this person not get in?", and the place every recovery action for
 // one account lives.
@@ -59,7 +59,7 @@ export default function AccountPanel({
   const lang = i18n.language;
   const qc = useQueryClient();
   const [link, setLink] = useState<{ url: string; expires_at: string | null } | null>(null);
-  const [copied, setCopied] = useState(false);
+  const { copied, copy: copyValue } = useCopyFeedback();
 
   const q = useQuery({
     queryKey: qk.adminUserAccess(user.id),
@@ -88,19 +88,11 @@ export default function AccountPanel({
     onError: (err) => notifyActionError(err, t("users.pendingAccess.activateFailed")),
   });
 
-  const copy = async () => {
-    if (!link) return;
-    // Via the shared helper, whose synchronous `execCommand` path is what makes copying work on a
-    // plain-http LAN origin — where `navigator.clipboard` is undefined, and which is exactly the
-    // minimal self-host this no-email link was built for.
-    if (await copyText(link.url)) {
-      setCopied(true);
-      window.setTimeout(() => setCopied(false), 2000);
-      return;
-    }
-    // The link is on screen and selectable, so a failed copy is a convenience that failed — not the
-    // action failing. Say so rather than leaving the button looking inert.
-    notify({ level: "warning", message: t("users.account.copyFailed") });
+  // Via the shared helper, whose synchronous `execCommand` path is what makes copying work on a
+  // plain-http LAN origin — where `navigator.clipboard` is undefined, and which is exactly the
+  // minimal self-host this no-email link was built for.
+  const copy = () => {
+    if (link) void copyValue(link.url);
   };
 
   const a: AdminUserAccess | undefined = q.data;