Front end of tier-3 larger messages. The composer body cap goes from 4000 to
16000 bytes (kHushChatMaxMessageChunks = 64 chunks ⇒ up to 4 transactions), so a
message past the single-transaction ceiling now actually composes and sends via
the tier-3 path. The buffer and static_assert grow to match.
The beside-the-gauge indicator (and its hover tooltip) now distinguish the two
tiers: while a long message still fits one transaction it shows the part count as
before; once it spills across several it shows the TRANSACTION count — the real
cost the user asked to see — and the tooltip explains it is split across several
transactions, the recipient sees it only once every part has arrived, so it takes
longer to deliver and costs a fee per transaction. New strings chat_txns_label /
chat_parts_explain_multi (English; 8 locales fall back pending a translation pass).
Tier 3 is now end to end: compose → split → broadcast → reassemble → display.
A receive-side "incoming N/M parts" progress hint remains a future refinement
(an incomplete large message simply appears once whole).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
DanSandClaude Opus 4.8
acb6446076