POST, GET and DELETE under /api/v1/chats/{id}/webhooks, for the chats
that GET /api/v1/chats lists. The webhooks are kept in
$DATA_DIR/webhooks.json, mode 0600, which each change replaces whole
through a temporary file in the same directory and a rename. bot.Run
reads the file before it starts the chat client: absent means none, and
a file that cannot be read aborts startup. Reading a JSON request body
moved into decodeBody, which the messages endpoint now shares. Nothing
is posted to a webhook yet.
Model: opus-5-5
`GET /api/v1/chats/{id}/messages?count=N` returns a chat's recent messages, oldest first (`count` 1 to 100, default 20), and `POST` to the same path sends a text message and returns it once the chat client has taken it. Both answer `404` for any id the chats list does not show, looked up in the same contact list. The message record is defined once, for the webhooks to reuse.
Disclosures: items are read five at a time, because one item can be many times its text and 100 at once could pass the 16 MiB read limit; text too long gets `413`, a contact who deleted the chat `409` (unverified for one still connecting); a query the server cannot read gets its own `400`.
Model: opus-5-5