Add category update-position endpoint

[PrestaEdit]

Questions	Answers
Branch?	dev
Description?	Fills the UpdateCategoryPositionCommand gap: PUT /categories/{categoryId}/positions (scope category_write) to reorder a category within its parent (parentCategoryId, way, positions list in "<index>_<parentId>_<categoryId>" format, foundFirst bool).
Type?	improvement
BC breaks?	no
Deprecations?	no
Fixed ticket?	Related to PrestaShop/PrestaShop#39630
How to test?	PUT /categories/{id}/positions with a positions payload (client granted category_write) reorders the category. Covered by CategoryPositionEndpointTest.
Possible impacts?	Reorders categories within their parent.

[mattgoud]

hey @PrestaEdit, thanks for this 🙏 heads up: there's an overlap with #325, which also adds this exact PUT /categories/{categoryId}/positions endpoint (same command, same scope, same CategoryPosition resource) as part of a slightly larger PR that also covers the root add/edit endpoints and closes PrestaShop/PrestaShop#41973.

#325 is a bit further along (already went through review), so to avoid both PRs conflicting on the same new file, would you mind closing this one in favour of #325? happy to credit your input there, and of course if you spot anything your version does better let me know and i'll fold it in 👍

[PrestaEdit]

Thanks for the heads up @mattgoud — you're right, #325 is the superset (root add/edit + this same position endpoint) and it's further along. Closing this in favour of yours. Your CategoryPosition is already a bit better than mine (Assert\NotBlank + the openapi example + the docblock on the legacy row-id prefix), no folding needed on my side.

[PrestaEdit]

Superseded by #325.