Stop auto-running AKSRT_Settings_Migration, drop multi-option settings
merge and Zibll favicon aliases, remove the migration tools entry from
menus/schema, flatten admin sections so pages are not demoted into a
compat bag, and retire the migration-status payload for leftover SPA
routes after a full admin rebuild.
Replace the post_list.list admin contract with a dedicated schema module
using Zibll keys (paging_ajax_s, paging_ajax_ias_s, ajax_trigger,
ajax_nomore, list_orderby, post_list_author/time, target_blank). Runtime
derives numbered/load_more/infinite from those keys and applies list
orderby on main queries without legacy dual-write layers.