The vendor file was misnamed jquery-1.12.4.min.js but contained v3.6.1.
Replaced with the correctly-named jquery-4.0.0.min.js (78 KB, up from 89 KB).
Compatibility check: none of the removed jQuery 4.0 APIs are used in
main.js — no $.isArray, $.isFunction, $.trim, $.type, $.parseJSON, etc.
All ajax/deferred/DOM methods in use ($.ajax, $.when, .done/.fail/.always,
.on, .prop, .css, .addClass etc.) remain in the full 4.0 build.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>