✨ refactor: unify model-select searching & UX across the dashboard

This patch standardises how all “model” (and related) `<Select>` components handle searching.

Highlights
• Added a shared helper `modelSelectFilter` to `helpers/utils.js` – performs case-insensitive  value-based matching, independent of ReactNode labels.
• Removed the temporary `helpers/selectFilter.js`; all components now import from the core helpers barrel.
• Updated Selects to use the new filter *and* set `autoClearSearchValue={false}` so the query text is preserved after a choice is made.

Affected components
• Channel editor (EditChannelModal) – channel type & model lists
• Tag editor (EditTagModal) – model list
• Token editor (EditTokenModal) – model-limit list
• Playground SettingsPanel – model selector

Benefits
✓ Consistent search behaviour across the app
✓ Better user experience when selecting multiple items
✓ Cleaner codebase with one canonical filter implementation

web/src/helpers/utils.js

@@ -557,3 +557,13 @@ export function setTableCompactMode(compact, tableKey = 'global') {
   modes[tableKey] = compact;
   writeTableCompactModes(modes);
 }
+
+// -------------------------------
+// Select 组件统一过滤逻辑
+// 解决 label 为 ReactNode（带图标等）时无法用内置 filter 搜索的问题。
+// 使用方式： <Select filter={modelSelectFilter} ... />
+export const modelSelectFilter = (input, option) => {
+  if (!input) return true;
+  const val = (option?.value || '').toString().toLowerCase();
+  return val.includes(input.trim().toLowerCase());
+};