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/MessageView.tsx

@@ -888,7 +888,7 @@ function AttachmentList({ attachments, accountId, email }: { attachments: EmailB
           const url = a.blobId ? client.downloadUrl(accountId, a.blobId, a.name ?? "attachment", a.type) : "#";
           const inlineUrl = a.blobId ? client.downloadUrl(accountId, a.blobId, a.name ?? "attachment", a.type, true) : "#";
           return (
-            <a key={a.blobId ?? i} className="attachment" href={url} download={a.name ?? undefined} title={`${a.name ?? "attachment"} (${formatSize(a.size)})`} onClick={(ev) => { if (viewable(a)) { ev.preventDefault(); setPreview(a); } }}>
+            <a key={a.blobId ?? i} className="attachment" href={url} download={a.name ?? undefined} title={`${a.name ?? translate("Attachment")} (${formatSize(a.size)})`} onClick={(ev) => { if (viewable(a)) { ev.preventDefault(); setPreview(a); } }}>
               <span className="att-icon">{a.type.startsWith("image/") && a.type !== "image/svg+xml" && a.blobId ? <img src={inlineUrl} alt="" loading="lazy" /> : attachmentIcon(a.type, a.name)}</span>
               <span className="att-text">
                 <span className="att-name">{a.name ?? "(unnamed)"}</span>