feat: bread bot hubs with threads/in-chat split, invite auto-accept, transcript interop, and peer trust

[daopunk]

Summary

• Rebrand translation hub copy to Bread Bot; slim !help vs descriptive !info / !explain, plus !help-threads / !help-in-chat / !help-transcription feature guides.
• Split product menus into !translation-threads and !translation-in-chat (legacy !translation redirects; near-miss aliases like !translate-in-chat / !translate-thread).
• Language Threads: !translate-me-thread, !leave, !enable-in-chat (tear down threads and apply pending in-chat enable); notify sidecars when switching to in-chat; sidecar welcome lists !help / !rename / !leave / !info; sidecar-only !commands for the compact thread command list.
• In-chat auto: group-wide !translate-all-on / !translate-all-off, per-person !translate-me-on / !translate-me-off, and !enable-threads to clear all in-chat auto and apply a pending !translate-me-thread subscribe when switching to Language Threads.
• Mutual exclusion between Language Threads and in-chat auto with pending-switch storage so a refused enable applies after !enable-in-chat or !enable-threads.
• Sidecar mapping: persist both Signal send ids (group.…) and internal ids; resolve inbound sidecar traffic via index, send-id lookup, or list_groups reconcile when ids drift after product switches.
• Hub privacy/attest: single translation-hub !privacy (covers both CVMs); !verify challenge strings labeled Translation: … / Transcription: … so paired-group dual replies are distinguishable.
• Transcription worker: post Voice Transcription menu on !transcription invite; default auto-transcribe off; !transcribe refuses when auto is already on.
• Auto-accept group invites by role: translation accepts all pending invites; transcription accepts only when the translation peer is already in the group (requires PEER_PHONE).
• Transcript ↔ in-chat interop: with !translate-all-on (or personal auto for the speaker), the translation bot translates transcription-bot 📝 Transcript: posts — does not skip when voice attachment metadata is present; strips the transcript label before detect/translate (same as manual !translate).
• Peer identity trust: on startup, trust PEER_PHONE via signal-cli (trust_all_known_keys) so paired bots can decrypt each other's group messages after re-registration (fixes silent miss of transcripts when the peer was UNTRUSTED).
• Signal client: group id resolution/cache helpers plus identity trust helpers for consistent send vs internal id handling.
• Docs: translation hub vs transcription worker hierarchy; in-chat / language-threads / voice guides; local-dev peer-trust notes.

Test plan

• !help / !info / !explain on translation bot — Bread Bot hub, threads vs in-chat menus, guides
• !translation redirect; !translation-threads / !translation-in-chat and near-miss aliases
• In-chat group-wide: !translate-all-on es en → quote-replies; !translate-all-off stops group-wide only
• In-chat personal: !translate-me-on es en for one author; personal pair wins over group-wide for that user
• !enable-threads clears group-wide + all personal in-chat auto; pending !translate-me-thread completes after a refused subscribe
• Language Threads: !translate-me-thread es; sidecar welcome lists thread commands; !commands works in sidecar only; !leave from sidecar; !enable-in-chat from main tears down and notifies threads
• After in-chat → threads switch, messages in existing sidecars still relay (internal/send id reconcile)
• Enabling in-chat while threads are active (or the reverse) refuses with switch hint; after enable switch, pending enable applies
• Hub !privacy (not role-suffixed); paired-group !verify <text> yields Translation/Transcription-labeled quotes
• !transcription invite posts Voice Transcription menu; auto-transcribe starts off; !transcribe-on then voice notes; !transcribe while auto on explains no need
• Translation bot auto-joins a new group invite; transcription bot joins only when translation peer is already a member (skips otherwise / when PEER_PHONE unset)
• Peer not UNTRUSTED on either bot (GET /v1/identities/{phone}); no Untrusted Identity send errors in logs after startup trust
• !translate-all-on + !transcribe-on → voice note → transcript → pair-language quote-reply from translation bot
• Manual quote !translate <lang> still works with or without auto
• npm run ci green