DRY pass #2, batch 5, F17: the web's smaller pairs (#5372)

- desktop/bridge.ts listen<T>(): the no-op-off-desktop event listener
  that onSynced, onCaptured and onReminderDue each wrote.
- size.ts roughSize(): one decimal below 10, none above, for the client
  download sizes (MB) and the storage line (GB).
- BaseModal's title prop draws the heading row and close button that
  LabelsModal and ShareDialog each built.
- SyncView: switchChannel and switchSource share recheck(); the four
  update-card radios render from two option lists.

Kept: the board's and the shell's is-typing guards (they ignore different
elements), the drawer's nav beside the palette's commands (one is a laid-
out list with tags between its entries, the other a command list), the
status pills (each colours differently), and plurals (the copy is the
operator's call, raised in #5371).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/src/views/AccountView.vue

@@ -14,6 +14,7 @@ import { formatDateTime } from "../notes/datetime";
 import { repo } from "../adapters";
 import type { StorageUse } from "../adapters/repo";
 import { useAction } from "../composables/useAction";
+import { roughSize } from "../size";
 
 // The signed-in person's own account (not admin): the native clients linked to it
 // (the desktop and Android apps sync with a device bearer token issued here), its
@@ -51,14 +52,9 @@ async function load() {
 // Attachment storage (#2939 §4): how much this account uses, against its limit.
 const storage = ref<StorageUse | null>(null);
 
-function gigabytes(bytes: number): string {
-  const gb = bytes / 1024 ** 3;
-  return `${gb < 10 ? gb.toFixed(1) : gb.toFixed(0)} GB`;
-}
-
 function storageLine(use: StorageUse): string {
-  const used = gigabytes(use.used_bytes);
-  return use.limit_bytes === null ? `${used} used` : `${used} of ${gigabytes(use.limit_bytes)} used`;
+  const used = roughSize(use.used_bytes, "GB");
+  return use.limit_bytes === null ? `${used} used` : `${used} of ${roughSize(use.limit_bytes, "GB")} used`;
 }
 
 async function link() {