T9.2 - CR-017: Actual Hours is still there, still optional, still counted

A guard, not a build. Removal was floated in the meeting and rejected -
Marlena tracks actual hours so they can be measured - and CLAUDE.md carries
that as a recorded decision. Verified after eight waves of change:

- Actual Hours exists in Closeout (wp_actual_hrs), persists through collect,
  and prints on the export
- it is OPTIONAL: a package closes with it empty (driven, not assumed)
- it rolls up per T6.4: rollup_check has pinned actual-hours aggregation at
  every level since wave 6, and /api/wps/metrics carries actual_hours in its
  buckets

The follow-up the done-when requires is logged as BL-023: a productivity
factor (actual / estimated) - the rollup endpoints already carry both sums,
so it is a presentation task awaiting its own item id and a placement call.

Verification: export_check.py extended to 20/20 (the CR-017 section).

Items: CR-017

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/reference/file-map.md

@@ -299,7 +299,7 @@ python tests/mreq_check.py           # CR-013 - lightweight request, end to end
 Wave 9 adds these:
 
 ```bash
-python tests/export_check.py         # CR-008 - the export, walked field by field  17 checks
+python tests/export_check.py         # CR-008/CR-017 - export walk + hours guard   20 checks
 ```
 
 **Three probes were re-pointed at `T7.1`.** `sections_check.py` 5b drove the live