AssetManager 0.5.5.51

MeshCentral category mapping UI

Moves the existing MeshCentral device-type to asset-category mapping from the general settings template to the MeshCentral synchronization page.
Adds a dedicated save action for the fallback category and MeshCentral types 1 through 8.
Keeps the existing configuration keys (meshcentral.fallback_category_id and meshcentral.category_mapping) and synchronization behavior unchanged.
Validates submitted category IDs server-side.
Removes the unreachable hidden MeshCentral category-mapping block from the general settings page.