Add WorkflowToggle and FormValidator plugins:

- Introduce `workflow_toggle.js` for toggling workflow visibility.
- Implement `form_validator.js` for form validation on submission.
- Register plugins with `AMBPlugins` for initialization.

src/autometabuilder/web/static/js/plugins/form_validator.js

@@ -0,0 +1,21 @@
+/**
+ * AutoMetabuilder - Form Validator
+ */
+(() => {
+    const FormValidator = {
+        init() {
+            document.querySelectorAll('form[data-validate]').forEach(form => {
+                form.addEventListener('submit', event => {
+                    if (!form.checkValidity()) {
+                        event.preventDefault();
+                        event.stopPropagation();
+                    }
+                    form.classList.add('was-validated');
+                });
+            });
+        }
+    };
+
+    window.FormValidator = FormValidator;
+    window.AMBPlugins?.register('form_validator', async () => FormValidator.init());
+})();

src/autometabuilder/web/static/js/plugins/workflow_toggle.js

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+/**
+ * AutoMetabuilder - Workflow Toggle
+ */
+(() => {
+    const WorkflowToggle = {
+        init() {
+            document.querySelectorAll('[data-workflow-toggle]').forEach(button => {
+                button.addEventListener('click', () => {
+                    const builder = window.WorkflowBuilder;
+                    if (builder && builder.textarea && typeof builder.toggleRaw === 'function') {
+                        builder.toggleRaw();
+                        return;
+                    }
+                    const textarea = document.getElementById('workflow-content');
+                    if (textarea) {
+                        textarea.classList.toggle('d-none');
+                    }
+                });
+            });
+        }
+    };
+
+    window.WorkflowToggle = WorkflowToggle;
+    window.AMBPlugins?.register('workflow_toggle', async () => WorkflowToggle.init());
+})();