Translate the 14 chat strings added by the backlog work (relative time, retry,
jump-to-latest, empty states, search, export, message-too-long, mute/unmute) into
de/es/fr/ja/ko/pt/ru/zh, added additively (no existing key overwritten).
Also fix a key collision the English pass introduced: the new empty-state
sub-hint reused "chat_empty_hint", which already meant the standalone list hint —
so English and the translations disagreed. Split it into a distinct
"chat_empty_start" for the "Start one with New conversation" sub-line, leaving
the original chat_empty_hint intact.
Rebuilt the CJK subset font: +3 glyphs (刚静音) for zh "刚刚"/"静音", 0 removed.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>