Move plugins to manifest, pin Docker version, add Makefile

- Add plugins.txt listing all plugins for reproducible installs
- Add Makefile with setup/start/stop/install-plugins targets
- Remove user/plugins/ from git tracking
- Pin Docker image to 1.7.49.5-ls244

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

plugins/form/templates/forms/fields/conditional/conditional.html.twig

@@ -1,19 +0,0 @@
-{% extends "forms/field.html.twig" %}
-
-{% block field %}
-{% set value = evaluate(field.condition) %}
-{% set value = value == 'true' ? 1 : value %}
-{% set value = value == 'false' ? 0 : value %}
-
-{% if value %}
-    {% if field.classes %}
-    <div class="{{ field.classes }}">
-    {% endif %}
-
-    {% include 'forms/default/fields.html.twig' with {name: field.name, fields: field.fields} %}
-
-    {% if field.classes %}
-    </div>
-    {% endif %}
-{% endif %}
-{% endblock %}