新增技能目录重新扫描接口与分页,关掉技能安全扫描的配置开关

- 后端新增 POST /api/skills/reconcile-custom:扫描 custom 目录,把磁盘存在但 DB 无记录的技能登记到调用者名下(published=false),附 4 个单元测试
- 前端技能列表加"重新扫描技能目录"按钮,列表分页每页 10 条
- SkillsConfig 新增 security_scan.enabled(默认 true)用于关闭 LLM 安全扫描;scan_skill_content 在开关关闭时直接放行
- 智能体卡片/对话页长名 truncate 显示 + loading 占位

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend-web/src/pages/AgentChatPage.tsx

@@ -60,7 +60,9 @@ export default function AgentChatPage() {
     hasPendingForThisAgent,
   );
 
-  const { agent } = useAgent(agent_id);
+  const { agent, isLoading: isAgentLoading } = useAgent(agent_id);
+  const agentDisplayName =
+    agent?.name ?? (isAgentLoading ? t.common.loading : "");
 
   const { threadId, setThreadId, isNewThread, setIsNewThread } =
     useThreadChat();
@@ -171,8 +173,11 @@ export default function AgentChatPage() {
             {/* Agent badge */}
             <div className="flex shrink-0 items-center gap-1.5 rounded-md border px-2 py-1">
               <BotIcon className="text-primary h-3.5 w-3.5" />
-              <span className="text-xs font-medium">
-                {agent?.name ?? agent_id}
+              <span
+                className="max-w-[200px] truncate text-xs font-medium"
+                title={agentDisplayName}
+              >
+                {agentDisplayName}
               </span>
             </div>
 
@@ -250,7 +255,7 @@ export default function AgentChatPage() {
                     context={settings.context}
                     extraHeader={
                       isLandingState && (
-                        <AgentWelcome agent={agent} agentName={agent?.name ?? agent_id} />
+                        <AgentWelcome agent={agent} agentName={agentDisplayName} />
                       )
                     }
                     disabled={env.NEXT_PUBLIC_STATIC_WEBSITE_ONLY === "true"}