feat: validate team slug format and improve error handling in team creation

hub/admin-web/src/routes/admin/org/[slug]/teams/+page.svelte

@@ -38,12 +38,19 @@
 		}
 	}
 
+	const SLUG_RE = /^[a-z0-9]([a-z0-9-]*[a-z0-9])?$/;
+
 	async function createTeam() {
 		if (!newSlug.trim() || !newName.trim()) return;
+		const teamSlug = newSlug.trim().toLowerCase();
+		if (!SLUG_RE.test(teamSlug)) {
+			toastError('标识须为小写字母数字，可用连字符连接');
+			return;
+		}
 		adding = true;
 		try {
 			await api.createTeam(slug, {
-				slug: newSlug.trim(),
+				slug: teamSlug,
 				name: newName.trim(),
 				...(newDesc.trim() ? { description: newDesc.trim() } : {})
 			});
@@ -134,7 +141,7 @@
 	<div class="saas-card-pad mb-6">
 		<h2 class="saas-section-title mb-4">新建团队</h2>
 		<div class="grid gap-3 md:grid-cols-[1fr_1fr_1.2fr_auto]">
-			<input class="saas-input" placeholder="标识（小写字母数字）" bind:value={newSlug} />
+			<input class="saas-input" placeholder="标识（如 math-g7）" bind:value={newSlug} />
 			<input class="saas-input" placeholder="名称" bind:value={newName} />
 			<input class="saas-input" placeholder="描述（可选）" bind:value={newDesc} />
 			<button class="saas-btn-primary" onclick={createTeam} disabled={adding}>新建</button>