## Bug
PR #345 (order_item_reason_policy wiring) accidentally broadened the
legacy
\`Notes is required for this product\` check to fire for every product
whose
POST body carried an empty/whitespace \`notes\` field.
Mobile POS step 2 always posts the primary product (e.g. Sættevognstræk,
product id 3) with \`notes: ''\` as part of
\`syncCurrentTransactionToOrder\`. After #345, the API started returning
400 for that primary item. The frontend silently swallowed the 400 in
the next-step click handler, and the operator saw **"Fuldfør doesn't
continue"** with no feedback.
## Repro
1. Log in to the mobile POS (e.g. dept 12 / Taulov)
2. Scan / type a customer's plates (e.g. EP68666 + GG1876)
3. Long-press Sættevognstræk to add the service
4. Tap **Fuldfør**
Before this fix: \`POST /order/items\` → 400 \`Notes is required for
this product\`. Frontend catches and logs \`Next-step action was
interrupted: AxiosError: Request failed with status code 400\`. Operator
sees no error in the UI.
After this fix: \`POST /order/items\` → 200 for the primary product; the
order completes normally.
## Fix
Scope the empty-notes rejection to products whose \`requires_note\` flag
(or extraordinary-chemistry special case) is set, matching the existing
PUT handler behaviour. Products that don't require notes can post
\`notes=''\` without rejection.
## Lock-in tests
Two Pest tests under \`Tests\\Api\\OrderItemsApiTest\`:
- \`allows empty notes for primary products that do not require a note\`
— \`requires_note=0\` product with \`notes=''\` returns 200
- \`still rejects empty notes for products whose requires_note flag is
enabled\` — \`requires_note=1\` product with \`notes=' '\` returns 400
with the legacy message
## Verification
PHP API suite: **292/292 passing** (11892 assertions). Local
\`scripts/php-ci-test.sh api\`.
## Companion PR
\`copenhagentruckwash/pleno-vue\` →
\`fix/fuldfor-surface-order-item-error\` will surface order-item API
errors in the UI so silent failures become visible. That PR is a
follow-up; this one is the actual root cause fix.
Co-authored-by: Truck Wash Agent <agent@copenhagentruckwash.local>
