collapse/extend results page tables

[tilen323]

Summary
Adds collapsible per-file result panels on the Plugin Check admin screen, with Collapse All / Expand All controls shown only when file result tables exist.

Changes

• Wrap each file’s results in a collapsible card (design: file icon, header bar, chevron, animated panel height).
• Add Collapse All / Expand All in a toolbar below export buttons; visible only after checks finish and only if at least one file table was rendered.
• Animate expand/collapse with interpolate-size and height transitions.
• Keep export button behavior unchanged (innerHTML reset on export container only).

Files

• templates/results-table.php,
• templates/admin-page.php
• assets/js/plugin-check-admin.js
• assets/css/plugin-check-admin.css
• includes/Admin/Admin_Page.php

Test plan

• Run check on plugin with issues → panels toggle; Collapse/Expand All work (including false positives).
• Run check with no issues → export row may show; Collapse/Expand All hidden.
• New check resets toolbar until complete again.

[github-actions]

The following accounts have interacted with this PR and/or linked issues. I will continue to update these lists as activity occurs. You can also manually ask me to refresh this list by adding the props-bot label.

Unlinked Accounts

The following contributors have not linked their GitHub and WordPress.org accounts: @tilen323.

Contributors, please read how to link your accounts to ensure your work is properly credited in WordPress releases.

If you're merging code through a pull request on GitHub, copy and paste the following into the bottom of the merge commit message.

Unlinked contributors: tilen323.

Co-authored-by: davidperezgar <davidperez@git.wordpress.org>

To understand the WordPress project's expectations around crediting contributors, please review the Contributor Attribution page in the Core Handbook.

[davidperezgar]

Hello @tilen323 ! Thanks for your contribution.
You need to fix the lint tests.