IMAP_EMAIL_SEED / POP3_EMAIL_SEED accept a directory (rglob *.eml +
*.json) or a single .json/.eml. Loaded entries CONCATENATE with the
hardcoded _BAIT_EMAILS — additive to the realism-engine emailgen
output rather than replacing it. JSON dicts require from_addr /
to_addr / subject / body; bare bodies are wrapped into RFC 5322 on
load. compose_fragment reads service_cfg["email_seed"] and bind-mounts
the host path read-only at /var/spool/decnet-emails/seed.
When IMAP_EMAIL_SEED / POP3_EMAIL_SEED points at a directory of .eml
files (the orchestrator emailgen worker's drop path,
/var/spool/decnet-emails/ by convention), the bait mailbox is replaced
with those LLM-generated, persona-driven, threaded messages. Empty /
missing dir keeps the hardcoded fallback so a fresh deployment is never
silent. Cached with mtime invalidation + a short TTL so a hot mailbox
doesn't pay the parse cost on every IMAP/POP3 command.
Replaces the DEBT-026 stub on both templates that named the env var but
never wired it through.
