refactor: DRY page layout wrapper in upses action routing

[somethingwithproof]

Problem

upses.php repeats the same page wrapper sequence (top_header(), renderer, bottom_footer()) in multiple action branches.

Proposed change

• introduce a shared UI layout wrapper helper
• route edit/list rendering branches through the helper
• keep behavior unchanged while reducing duplicated wrapper logic

Tests

• add standalone regression test for wrapper call ordering and callback execution
• include a routing assertion that action branches use the shared helper
• run syntax checks for touched files