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/admin/themes/grav/app/utils/selectize-option-click.js

@@ -1,42 +0,0 @@
-import $ from 'jquery';
-import Selectize from 'selectize';
-
-Selectize.define('option_click', function(options) {
-    const self = this;
-    const setup = self.setup;
-    this.setup = function() {
-        setup.apply(self, arguments);
-        let clicking = false;
-
-        // Detect click on a .clickable
-        self.$dropdown_content.on('mousedown click', function(e) {
-            const target = $(e.target);
-            if (target.hasClass('clickable') || target.closest('.clickable').length) {
-                if (e.type === 'mousedown') {
-                    clicking = true;
-                    self.isFocused = false; // awful hack to defuse the document mousedown listener
-                } else {
-                    self.isFocused = true;
-                    setTimeout(function() {
-                        clicking = false; // wait until blur has been preempted
-                    });
-                }
-            } else { // cleanup in case user right-clicked or dragged off the element
-                clicking = false;
-                self.isFocused = true;
-            }
-        });
-
-        // Intercept default handlers
-        self.$dropdown.off('mousedown click', '[data-selectable]').on('mousedown click', '[data-selectable]', function() {
-            if (!clicking) {
-                return self.onOptionSelect.apply(self, arguments);
-            }
-        });
-        self.$control_input.off('blur').on('blur', function() {
-            if (!clicking) {
-                return self.onBlur.apply(self, arguments);
-            }
-        });
-    };
-});