fix(bot-mode): dead chat pin adopts the existing hidden Bot Chat instead of reintroducing the bot

[teknium1]

Summary

Opening a bot no longer reintroduces it on a fresh session when its pinned chat id has gone stale — it adopts the profile's existing (hidden) Bot Chat and its full history instead.

Reported live (Windows, after an update): bots opened to a new "introduce yourself" session and the forever-chat history looked gone; some profiles were left on fresh chats. The messages were never lost — only the pin was.

Root cause

A bot's canonical-chat pin (ui_meta.hermes-bots.chat) can point at a session id that was never persisted or was rewritten past recovery (a "dead pin"). On a dead pin, profiles.list returns preferred_session: null, and openBotCanonicalChat's recovery branches relied on last_session / preferred_session for an adoptable history. Both are computed from a hidden-excluding query, and Bot Mode sessions are hidden by design — so the real Bot Chat (intact on disk) was never found, and every open fell through to createCanonicalChat, minting a new intro.

Fix

• findExistingCanonicalBotChat(name): browse the profile's hidden sessions via session.list { include_hidden: true } (the same view the Bots Sessions submenu uses) and return the existing "Bot Chat" id.
• adoptOrCreateCanonicalChat(name): adopt that chat (open + re-pin) if present; mint a fresh one only when there is genuinely none.
• All three mint-new branches in openBotCanonicalChat (no-pin/no-history, bad-pin-resolves-to-non-BotChat, definitively-gone) now route through it. The bot is reintroduced ONLY when there is truly no forever-chat.

Validation

	Result
hermes-bots suite	335/335 pass
New adopt tests	3/3 pass; 3/3 fail on reverted plugin (sabotage-checked)
Live E2E over gateway RPC (real profile DB)	dead pin → preferred_session=null → session.list finds hidden Bot Chat → session.resume returns real history (4 msgs), not a new intro

Reproduced the exact user symptom first (dead pin in profile.yaml, real Bot Chat hidden on disk → old code mints intro), then confirmed the fix resolves to the real chat.

Note: the user's damaged profiles are recoverable — their old Bot Chats are hidden+unpinned on disk, and this fix re-adopts them on next open. A one-time pin-repair for already-nulled pins can follow if wanted.

Infographic

[teknium1]

Superseded by #90738, which bundles this dead-pin adopt fix together with the ownership-file preservation (#89298) and the GUI-handoff backend reap that fixes the same update-incident end to end. Same adopt commit is included there.