Synced messages only store a plain-text extract; HTML-only emails end up empty or truncated

Summary Problem The Message object stores only a single 'text' field. For emails that only have an HTML part (common for newsletters and automated notifications, observed on roughly 2-3% of synced messages in production), this text extract is sometimes empty or severely truncated, and there is no separate HTML/raw body field available through the API to fall back on. Proposed solution Store (or optionally expose via the API) the original HTML body alongside the plain-text extract, so client applications built on top of Twenty's message sync can render the full content instead of a blank or partial message for this subset of emails. Additional context Worked around, for the subset of mailboxes with IMAP access, by fetching the original message directly from the mail server via its Message-ID when the synced text looked suspiciously short. This only works for IMAP-accessible mailboxes, not for the primary Gmail-connected account, so a portion of affected messages remai…