Translate English built from template literals in attributes

i18n-literals now flags a template literal in a UI attribute or prop when
there are words between its values: `Remove ${email}`, `${name} — shared by
${owner}`. It cannot be a catalogue key as written, so neither the key
exemption nor the sentence-shape test applies. A template that is only
punctuation around values, like `${name} (${size})`, is left alone.

The twelve it found are now keys with placeholders: the quota bar title,
the address menu's label, a folder's subfolder unread count, a recipient
chip's remove button, the contact editor's title, shared and available
calendars and address books, the date and time fields' labels, the
attachment title's fallback name, and the free/busy bar. The bar showed
the raw JMAP busyStatus ("confirmed") and now says Busy, Tentative or
Unavailable.

11 new keys in all nine catalogues. Remove {address}, Date, Time, Busy and
Tentative already existed.

web/src/views/mail/MailboxTree.tsx

@@ -369,7 +369,7 @@ function FolderRow({ mailbox: m, label, depth, hasChildren, open, hiddenUnread,
       </span>
       <span className="folder-icon" style={tint ? ({ "--folder-color": tint } as React.CSSProperties) : undefined}>{icon}</span>
       <span className="nav-label">{label}</span>
-      {count > 0 && <span className="nav-count" title={hiddenUnread ? `${own} here, ${hiddenUnread} in subfolders` : undefined}>{count > 9999 ? "9999+" : count}</span>}
+      {count > 0 && <span className="nav-count" title={hiddenUnread ? t("{here} here, {inSubfolders} in subfolders", { here: own, inSubfolders: hiddenUnread }) : undefined}>{count > 9999 ? "9999+" : count}</span>}
       {count > 0 && <span className="nav-dot" />}
       <button
         className="icon-btn nav-more"