/code-review high round 1 (5 findings):
- iso(dt) now typed `date | None` — MediaAsset.upload_date is a plain `date`, not a
datetime; the helper's signature was too narrow for the type-contract epic. +test.
- restore alphabetical app.* import order in audit.py and plex.py (the new iso/_common
imports had been dropped in mid-block).
The other 3 findings are deliberate design choices, left as-is for UAT: push/push-plan
now gate write-scope before the 404 (dependency ordering); the unified 403 message; and
owned_or_404's owner_attr kept for S1b's DownloadShare.to_user_id-style owners.
Gate: ruff clean, pytest 164 green.
peter
cf8bbad8a1