docs(time): fix response examples

[Sean-Kenneth-Doherty]

Summary

• update the Time server README response examples to include the emitted day_of_week field
• correct the convert_time example source/target datetimes and +14.0h offset
• add a regression test that parses README response JSON blocks and compares them with actual TimeServer output under frozen dates

This covers the trailing-comma issue from #4142, but also fixes the stale example payloads themselves.

Validation

• cd src/time && uv run pytest -q on current upstream main: 39 passed
• cd src/time && uv run ruff check .
• local merge of this fork-pushable branch with current origin/main completed without conflicts
• cd src/time && uv run pytest -q in the local merged state: 39 passed

[Sean-Kenneth-Doherty]

Closing this draft as a duplicate of #4174. The open PR already carries the same Time README/test changes and has passing hosted checks, so keeping this draft around would just add maintainer noise.