feat: typed script parameters with validation and icon-grid selector

- Add ScriptParameterConfig model (string, integer, float, boolean, select types)
- Server-side validation at both define-time and execute-time
- Parameters passed as SCRIPT_PARAM_* environment variables
- Web UI parameter editor in script create/edit dialog (add/remove/reorder)
- Icon-grid selector component (ported from wled-screen-controller)
- Replace audio device dropdown with icon-grid selector
- Replace callback event dropdown with icon-grid selector
- Localization for parameter UI (en, ru)

media_server/static/js/callbacks.js

@@ -3,10 +3,34 @@
 // ============================================================
 
 import { t, showToast, escapeHtml, closeDialog, showConfirm, getAuthHeaders, hasCredentials } from './core.js';
+import { IconSelect } from './icon-select.js';
+import { callbackEventIcons } from './icons.js';
 
 export let callbackFormDirty = false;
 export function setCallbackFormDirty(value) { callbackFormDirty = value; }
 
+let _callbackEventIconSelect = null;
+
+function _ensureCallbackEventIconSelect() {
+    if (_callbackEventIconSelect) return;
+    const select = document.getElementById('callbackName');
+    if (!select) return;
+
+    const items = Object.entries(callbackEventIcons).map(([value, icon]) => ({
+        value,
+        icon,
+        label: value,
+    }));
+
+    _callbackEventIconSelect = new IconSelect({
+        target: select,
+        items,
+        columns: 3,
+        placeholder: t('callbacks.placeholder.event'),
+        onChange: () => { callbackFormDirty = true; },
+    });
+}
+
 let _loadCallbacksPromise = null;
 export async function loadCallbacksTable() {
     if (_loadCallbacksPromise) return _loadCallbacksPromise;
@@ -71,6 +95,9 @@ export function showAddCallbackDialog() {
     document.getElementById('callbackName').disabled = false;
     title.textContent = t('callbacks.dialog.add');
 
+    _ensureCallbackEventIconSelect();
+    if (_callbackEventIconSelect) _callbackEventIconSelect.setValue('', false);
+
     callbackFormDirty = false;
 
     document.body.classList.add('dialog-open');
@@ -101,6 +128,9 @@ export async function showEditCallbackDialog(callbackName) {
         document.getElementById('callbackIsEdit').value = 'true';
         document.getElementById('callbackName').value = callbackName;
         document.getElementById('callbackName').disabled = true;
+
+        _ensureCallbackEventIconSelect();
+        if (_callbackEventIconSelect) _callbackEventIconSelect.setValue(callbackName, false);
         document.getElementById('callbackCommand').value = callback.command;
         document.getElementById('callbackTimeout').value = callback.timeout;
         document.getElementById('callbackWorkingDir').value = callback.working_dir || '';