NPM: Add `jquery`for ILIAS 12

[fhelfer]

This PR adds jQuery as NPM dependency.

Usage:

• In many components, searching for $( results in 3700+ occurrences

Wrapped By:

• Not applicable

Reasoning:

• jQuery is a long-standing dependency in ILIAS, providing DOM manipulation, event handling, and AJAX utilities.
  While modern browsers now support most of these features natively, a full migration away from jQuery would require significant effort across many components.
  For now, keeping it ensures compatibility and avoids regressions in a large number of modules.

Maintenance:

• jQuery remains actively maintained and has an existing security policy (https://github.com/jquery/jquery/blob/02cf4ee090debded3da4b0e3f59bd33f516125ea/SECURITY.md).
• (The latest release is from 28.08.2023)
• Currently v4 is being released in Beta with the last update from 11.08.2025)

Links:

• NPM: https://www.npmjs.com/package/jquery
• GitHub: https://github.com/jquery/jquery
• Documentation: https://api.jquery.com/

[matthiaskunkel]

Jour Fixe, 08 DEC 2025: Dependency is accepted for ILIAS 12. We could get rid of this dependency when we replace jQuery usages by e.g. Vanilla JS.