AI coding timezone regression lab

Requirements: a supported Python version (tested 3.12.14) and IANA time zone data.
Python zoneinfo uses system data or the first-party tzdata package.
If needed in your own virtual environment: python -m pip install tzdata

All data is synthetic. Tests use SQLite :memory:. No model API is called.

1. Run the supplied fixed version:
   python3 -m unittest -v test_report test_review
   Expected: 10 tests, OK.

2. Reproduce the initial failure (keep the fixed version first):
   cp report.py report-fixed.py
   cp report-before.py report.py
   python3 -m unittest -v test_report
   Expected: 8 tests, 6 failures. Nonzero exit code is expected.

3. Ask your coding assistant to fix report.py with tests held unchanged,
   or restore the supplied fixed version:
   cp report-fixed.py report.py
   python3 -m unittest -v test_report test_review

Only local midnight boundaries that resolve to one instant are supported.
Missing/ambiguous midnight is rejected; this lab is not a universal civil-date API.
DB field created_at is a UTC Unix timestamp in integer seconds.
Business selection remains status='paid', sums are integer cents.
No production repository, database, account or real order is used.
