notion: a comment's created_time and last_edited_time keep their seconds and have no milliseconds, where real gives the minute #1110

Found while reviewing #1098.

Source and commit — notion (GET /v1/comments), main at 426d4b08. list_comments in backlot/routers/notion.py writes a comment's created_time and last_edited_time with synth.rfc3339: to the second, with no milliseconds.

How you know — measured against api.notion.com on 2026-10-27 with an internal integration's token under Notion-Version: 2025-09-03, on a page of our own workspace: the first three comments GET /v1/comments?block_id= listed each answered created_time and last_edited_time 2026-10-20T16:50:00.000Z, zero seconds and milliseconds. That is the form real gives a page's, a block's and a data source's timestamps, which is #882.

Reproduction — one record, over backlot.serve():

import json
import urllib.request

import backlot

records = [
    {"source_type": "notion", "doc_id": "page", "teamspace": "eng", "title": "Page", "content": "Body.",
     "author_email": "ava@acme.com", "visibility": "public",
     "created": "2026-03-01T08:15:42Z", "updated": "2026-03-02T09:30:17Z",
     "comments": [{"author_email": "ava@acme.com", "body": "Looks good.",
                   "created_ts": "2026-03-02T10:20:33Z"}]},
]

with backlot.serve(records) as s:
    h = {"Authorization": f"Bearer {s.token}", "Notion-Version": "2025-09-03",
         "Content-Type": "application/json"}

    def call(method, path, body=None):
        data = None if body is None else json.dumps(body).encode()
        req = urllib.request.Request(f"{s.base_url}/notion/v1/{path}", data=data, method=method, headers=h)
        with urllib.request.urlopen(req) as r:
            return json.load(r)

    (page,) = call("POST", "search", {})["results"]
    (comment,) = call("GET", f"comments?block_id={page['id']}")["results"]
    print(comment["created_time"], comment["last_edited_time"])

prints 2026-03-02T10:20:33Z 2026-03-02T10:20:33Z on 426d4b08, where real's form for that minute is 2026-03-02T10:20:00.000Z.

1. A comment's timestamps keep their seconds and have no milliseconds

Request — GET /v1/comments?block_id={page_id}.

Backlot serves — "created_time":"2026-03-02T10:20:33Z" and the same last_edited_time for a comment the corpus dates 10:20:33.

The real API serves — the minute with zero seconds and milliseconds: "2026-10-20T16:50:00.000Z" for each comment measured, in both fields.

Can a client tell? Not from the status. The strings differ on the wire: in the milliseconds always, and in the seconds wherever the corpus dates a comment past the minute's start.