feat(tui): add fuzzy search to model picker

- Add SearchableSelectList component with fuzzy filtering
- Integrate with /models command for quick model search
- Support up/down navigation while typing
- Uses pi-tui's fuzzyFilter for intelligent matching

src/tui/components/selectors.ts

@@ -1,10 +1,15 @@
 import { type SelectItem, SelectList, type SettingItem, SettingsList } from "@mariozechner/pi-tui";
-import { selectListTheme, settingsListTheme } from "../theme/theme.js";
+import { searchableSelectListTheme, selectListTheme, settingsListTheme } from "../theme/theme.js";
+import { SearchableSelectList } from "./searchable-select-list.js";
 
 export function createSelectList(items: SelectItem[], maxVisible = 7) {
   return new SelectList(items, maxVisible, selectListTheme);
 }
 
+export function createSearchableSelectList(items: SelectItem[], maxVisible = 7) {
+  return new SearchableSelectList(items, maxVisible, searchableSelectListTheme);
+}
+
 export function createSettingsList(
   items: SettingItem[],
   onChange: (id: string, value: string) => void,