The typing indicator rendered "<role name> is typing…". Show a generic
"AI is typing…" instead and keep the role/identity name only in the
dimmed interlocutor label above the typing dots.
- typing line now always renders t("AI is typing…")
- add the "AI is typing…" key to en-US and ru-RU locales
- sync stale doc comments that referenced the old text
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>