The helper used log.overtime (which doesn't exist on WorkLog); the
correct field is overtime_amount. Combined with a defensive
`getattr(..., None) or 0`, the bug made the flag permanently False,
which would have silently hidden the 'Price now' banner in Tasks 3
and 4. Now reads overtime_amount directly (it's non-nullable with a
0.00 default, so no defensive shim is needed).
Adds 4 regression tests:
- test_overtime_needs_pricing_flag: the bug that just got fixed
- test_query_count_is_bounded: N+1 guard (4 queries regardless of worker count)
- test_empty_log_returns_zero_totals: log with no workers attached
- test_log_without_team_has_no_pay_period: log whose team became NULL
Also removes unused `reverse` import from tests.py.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
b0aa35661b