chore: use the API timestamp format in fixtures and docstrings

[felipefreitag]

What

The API returns timestamps in Postgres text format: YYYY-MM-DD HH:MM:SS[.ffffff]+00 (for example 2023-10-06 23:47:56.678+00). Our test fixtures and docstrings showed ISO 8601 for response fields. This PR makes them match the real API output.

• Convert 276 response-fixture timestamps in 40 test files to Postgres format.
• Remove the ISO 8601 claims from response-field docstrings (5 source files). The wording now matches the API reference.
• Fix 3 webhook data.created_at fixtures from …894719+00:00 to …894Z. Real webhooks emit millisecond precision with Z.

What stays ISO 8601 on purpose

• scheduled_at as a request parameter. The API accepts ISO there.
• Webhook event payloads. Webhooks emit ISO with millisecond precision.
• revoked_at in the revoke OAuth grant response. That endpoint returns ISO.

Why

The SDK never parses these values, so there are no runtime changes. But wrong fixtures propagate: new endpoints copy the pattern, and users who read the tests get the wrong contract.

Verification

• pytest: 558 passed.
• tox -e lint: OK.
• tox -e mypy: no issues in 176 files.

---

Summary by cubic

Align fixtures and docstrings with the API’s timestamp format (Postgres text). No runtime behavior changes.

• Refactors
  • Converted response fixtures to Postgres timestamps (e.g., "2023-10-06 23:47:56.678+00") across tests.
  • Updated response-field docstrings to remove ISO 8601 claims and match the API reference.
  • Fixed webhook event payload fixtures to ISO with millisecond precision and Z; kept ISO where the API uses it: the scheduled_at request param, webhook payloads, and revoked_at in the revoke OAuth grant response.

^{Written for commit 0eef200. Summary will update on new commits.}

[klotty]

No issues found across 45 files

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

<sub>Auto-approved: Updates test fixtures and docstrings to match the API's actual timestamp format (Postgres text). No runtime behavior changes; purely cosmetic/test alignment with no operational, security, or data tradeoffs.

Re-trigger cubic</sub>