[feature] Enhance Browser Steps tab to support full JavaScript/TypeScript Playwright scripts

A “Custom Playwright” mode where you drop in your .js or .ts file.
A initial run upon saving / confirming the browser steps to ensure that the code is actually valid.
Once the script finishes, the visual filters/change detection kicks in.

Perhaps an additional disclaimer / confirmation required to advise the user that unsecured self hosted instances can result in vulnerabilities, and to "only proceed if you know what you are doing".

The issue names the Browser Steps tab, Custom Playwright mode, saving or confirming browser steps, and the visual filters/change-detection phase, but no files or tests. Start by locating the existing Browser Steps and Playwright execution entry points. Done means full .js/.ts scripts can be validated on confirmation, executed, passed through change detection, and accompanied by an appropriate security warning.

Written by the indexing model from the issue text.