feat(hub): usage fact breakdown API + admin usage/session UI + release v0.0.34

Expose UsageFact kind/capability rollups on org and project usage reports,
and add admin pages that separate model tokens from external-capability meters.

hub/admin-web/src/routes/+layout.svelte

@@ -20,6 +20,7 @@
 
 	const navItems = [
 		{ key: 'overview', label: '概览', icon: 'overview' as const },
+		{ key: 'usage', label: '用量', icon: 'overview' as const },
 		{ key: 'members', label: '成员', icon: 'members' as const },
 		{ key: 'teams', label: '团队', icon: 'teams' as const },
 		{ key: 'projects', label: '项目', icon: 'projects' as const },
@@ -81,10 +82,10 @@
 		if (key === 'overview') return `/admin/org/${slug}`;
 		return `/admin/org/${slug}/${key}`;
 	}
-
 	function pageTitle(): string {
 		const key = activeKey();
 		if (key === 'overview' || key === '') return '概览';
+		if (key === 'sessions') return '会话详情';
 		return navItems.find((i) => i.key === key)?.label ?? '管理后台';
 	}