request = self._build_create_message_request("chat_id", body)

When cron job delivery targets a user's open_id (prefix ou_), Feishu API rejects it with:

[230001] Your request contains an invalid request parameter, ext=invalid receive_id

Because ou_xxx is not a valid chat_id — it's an open_id, and requires receive_id_type="open_id".

Expected

receive_id_type should be inferred from the ID prefix:

┌────────┬──────────┬─────────────────┐
│ Prefix │   Type   │ receive_id_type │
├────────┼──────────┼─────────────────┤
│ ou_    │ open_id  │ open_id         │
├────────┼──────────┼─────────────────┤
│ on_    │ union_id │ union_id        │
├────────┼──────────┼─────────────────┤
│ oc_    │ chat_id  │ chat_id         │
└────────┴──────────┴─────────────────┘

Suggested Fix

if chat_id.startswith("ou_"):
    rid_type = "open_id"
elif chat_id.startswith("on_"):
    rid_type = "union_id"
else:
    rid_type = "chat_id"
request = self._build_create_message_request(rid_type, body)

Reproduce

1. Create a cron job with deliver: "feishu:ou_xxxxx"
2. Job executes successfully but delivery fails with invalid receive_id
3. Group targets (oc_) work fine since they match the hardcoded "chat_id" type