The media.* rules were duplicated across the web update request and both API
requests (and diverged: web requires hosted id+path and tracks source; the API
accepts a bare external url it downloads). Pull them into one
App\Support\PostMediaRules::rules(hosted:) — same pattern as PostPlatformMetaRules
— parameterized by contract, so there's a single place to add a media key and the
validated()-strips-unlisted-keys footgun can't drift between entry points.
Behavior is unchanged (each ruleset is reproduced exactly). Web store keeps its
loose 'media' => array (no item rules) and is left out on purpose — adding strict
rules there would change the web create contract.
1242cc7384