feat(hub): add SearchableSelectField component and update RoleCard to use it

hub/admin-web/src/lib/components/RoleCard.svelte

@@ -5,6 +5,7 @@
 	import { fmtDate } from '$lib/format';
 	import { TOOL_OPTIONS } from '$lib/constants';
 	import SelectField from '$lib/components/SelectField.svelte';
+	import SearchableSelectField from '$lib/components/SearchableSelectField.svelte';
 	import CheckboxControl from '$lib/components/CheckboxControl.svelte';
 	import Icon from '$lib/components/Icon.svelte';
 	import { toastError, toastSuccess } from '$lib/toast';
@@ -60,10 +61,15 @@
 		{} as Record<string, typeof TOOL_OPTIONS>,
 	);
 
-	const modelItems = $derived([
-		{ value: '', label: '（使用平台默认模型）' },
-		...models.map((m) => ({ value: m.id, label: `${m.label}（${m.id}）` })),
-	]);
+	const modelItems = $derived.by(() => {
+		const fromCatalog = models.map((m) => ({ value: m.id, label: `${m.label}（${m.id}）` }));
+		const items = [{ value: '', label: '（使用平台默认模型）' }, ...fromCatalog];
+		// Keep a previously saved model selectable even if it left the live catalog.
+		if (defaultModel !== '' && !items.some((item) => item.value === defaultModel)) {
+			items.push({ value: defaultModel, label: `${defaultModel}（当前已存，不在目录中）` });
+		}
+		return items;
+	});
 
 	const skillItems = $derived(skills.map((s) => ({ value: s.name, label: s.name })));
 
@@ -160,7 +166,13 @@
 
 	<div class="mt-4">
 		<p class="saas-label">默认模型</p>
-		<SelectField items={modelItems} bind:value={defaultModel} />
+		<SearchableSelectField
+			items={modelItems}
+			bind:value={defaultModel}
+			placeholder="选择模型…"
+			searchPlaceholder="搜索模型名称或 ID"
+			emptyText="无匹配模型"
+		/>
 	</div>
 
 	<div class="mt-4">

hub/admin-web/src/lib/components/SearchableSelectField.svelte

@@ -0,0 +1,102 @@
+<script lang="ts">
+	import { Combobox } from 'bits-ui';
+	import Icon from './Icon.svelte';
+	import type { SelectItem } from './SelectField.svelte';
+
+	let {
+		items,
+		value = $bindable(''),
+		class: className = '',
+		disabled = false,
+		placeholder = '请选择…',
+		searchPlaceholder = '搜索…',
+		emptyText = '无匹配项',
+		onchange,
+	}: {
+		items: SelectItem[];
+		value?: string;
+		class?: string;
+		disabled?: boolean;
+		placeholder?: string;
+		searchPlaceholder?: string;
+		emptyText?: string;
+		onchange?: (value: string) => void;
+	} = $props();
+
+	let searchValue = $state('');
+
+	const filteredItems = $derived.by(() => {
+		const q = searchValue.trim().toLowerCase();
+		if (q === '') return items;
+		return items.filter(
+			(item) => item.label.toLowerCase().includes(q) || item.value.toLowerCase().includes(q),
+		);
+	});
+</script>
+
+<Combobox.Root
+	type="single"
+	{items}
+	{disabled}
+	{value}
+	allowDeselect={false}
+	onValueChange={(next) => {
+		value = next;
+		onchange?.(next);
+	}}
+	onOpenChangeComplete={(open) => {
+		if (!open) searchValue = '';
+	}}
+>
+	<div class="relative {className}">
+		<Combobox.Input
+			class="saas-combobox-input"
+			{disabled}
+			{placeholder}
+			aria-label={searchPlaceholder}
+			oninput={(e) => {
+				searchValue = e.currentTarget.value;
+			}}
+		/>
+		<Combobox.Trigger
+			class="absolute inset-y-0 right-0 flex w-9 items-center justify-center text-surface-600 disabled:cursor-not-allowed disabled:opacity-55"
+			{disabled}
+			aria-label="展开选项"
+		>
+			<svg
+				class="h-4 w-4 shrink-0"
+				viewBox="0 0 24 24"
+				fill="none"
+				stroke="currentColor"
+				stroke-width="1.75"
+				aria-hidden="true"
+			>
+				<path stroke-linecap="round" stroke-linejoin="round" d="M8.25 15l3.75 3.75L15.75 15" />
+				<path stroke-linecap="round" stroke-linejoin="round" d="M8.25 9l3.75-3.75L15.75 9" />
+			</svg>
+		</Combobox.Trigger>
+	</div>
+	<Combobox.Portal>
+		<Combobox.Content class="saas-select-content" sideOffset={6} collisionPadding={8}>
+			<Combobox.Viewport class="max-h-72 overflow-y-auto p-1">
+				{#each filteredItems as item (item.value)}
+					<Combobox.Item
+						class="saas-select-item"
+						value={item.value}
+						label={item.label}
+						disabled={item.disabled}
+					>
+						{#snippet children({ selected })}
+							<span class="min-w-0 flex-1 truncate">{item.label}</span>
+							{#if selected}
+								<Icon name="check" class="ml-2 h-4 w-4 shrink-0 text-primary-600" />
+							{/if}
+						{/snippet}
+					</Combobox.Item>
+				{:else}
+					<div class="px-2 py-2 text-sm text-surface-600">{emptyText}</div>
+				{/each}
+			</Combobox.Viewport>
+		</Combobox.Content>
+	</Combobox.Portal>
+</Combobox.Root>