Keep messages already collected in the current poll cycle when a stale
IMAP connection dies mid-fetch, so retrying once does not drop emails
that were already parsed and marked seen. Add a regression test covering
a mid-cycle disconnect after the first message succeeds.
Made-with: Cursor
Previously, `autoReplyEnabled=false` would block ALL email sends,
including proactive emails triggered from other channels (e.g., asking
nanobot on Feishu to send an email).
Now `autoReplyEnabled` only controls automatic replies to incoming
emails, not proactive sends. This allows users to disable auto-replies
while still being able to ask nanobot to send emails on demand.
Changes:
- Check if recipient is in `_last_subject_by_chat` to determine if
it's a reply
- Only skip sending when it's a reply AND auto_reply_enabled is false
- Add test for proactive send with auto_reply_enabled=false
- Update existing test to verify reply behavior
When _processed_uids exceeds 100k entries, the entire set was cleared
with .clear(), allowing all previously seen emails to be re-processed.
Now evicts the oldest 50% of entries, keeping recent UIDs to prevent
duplicate processing while still bounding memory usage.
Fixes#890
