feat(skills/settings): 技能复制 + 设置持久化等会话前改动

- 技能复制:新增 POST 复制接口(_rewrite_skill_frontmatter_name 重写 frontmatter name + 校验 + 去重),前端 skills api/hooks 与技能设置页配套
- 设置持久化:lastAgentId、线程 RAG 模式锁(settings/index、local)
- i18n(en/zh/types)、agent-card/input-box/message-list 等页面文案与交互微调
- scheduler/element.py 小修

(本批为会话前已存在的工作区改动,按要求一并提交;构建产物 backend.zip 未提交)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend-web/src/components/workspace/settings/skill-settings-page.tsx

@@ -7,6 +7,7 @@ import {
   ChevronLeftIcon,
   ChevronRightIcon,
   ClockIcon,
+  CopyIcon,
   FileArchive,
   GlobeIcon,
   InfoIcon,
@@ -50,6 +51,7 @@ import {
   ItemContent,
   ItemDescription,
 } from "@/components/ui/item";
+import { Input } from "@/components/ui/input";
 import { Tabs, TabsList, TabsTrigger } from "@/components/ui/tabs";
 import { SkillDetailDialog } from "@/components/workspace/skills/skill-detail-dialog";
 import { TagChipList } from "@/components/workspace/tags/tag-chip";
@@ -61,6 +63,7 @@ import { useI18n } from "@/core/i18n/hooks";
 import type { ValidateSkillUploadResponse } from "@/core/skills/api";
 import {
   useDeleteCustomSkill,
+  useDuplicateSkill,
   useInstallSkillUpload,
   useReconcileCustomSkills,
   useSetSkillPinned,
@@ -390,9 +393,12 @@ export function SkillRow({
   const setPublished = useSetSkillPublished();
   const setPinned = useSetSkillPinned();
   const deleteSkill = useDeleteCustomSkill();
+  const duplicateSkillMutation = useDuplicateSkill();
   const [confirmDeleteOpen, setConfirmDeleteOpen] = useState(false);
   const [tagPickerOpen, setTagPickerOpen] = useState(false);
   const [detailOpen, setDetailOpen] = useState(false);
+  const [duplicateOpen, setDuplicateOpen] = useState(false);
+  const [duplicateName, setDuplicateName] = useState("");
 
   const isCustom = skill.category === "custom";
   // Built-in flag falls back to "no DB owner" so legacy responses without
@@ -428,6 +434,31 @@ export function SkillRow({
     }
   }
 
+  function handleOpenDuplicate() {
+    // Suggest a "<name>-copy" default that already satisfies the backend's
+    // lowercase/digit/-/_ skill-name rule. The user can edit it before saving.
+    setDuplicateName(`${skill.name}-copy`);
+    setDuplicateOpen(true);
+  }
+
+  async function handleDuplicate() {
+    const target = duplicateName.trim();
+    if (!target) {
+      toast.error("请输入新技能名称");
+      return;
+    }
+    try {
+      const result = await duplicateSkillMutation.mutateAsync({
+        sourceName: skill.name,
+        newName: target,
+      });
+      toast.success(`已复制为「${result.skill_name}」`);
+      setDuplicateOpen(false);
+    } catch (err) {
+      toast.error(err instanceof Error ? err.message : String(err));
+    }
+  }
+
   async function handleTogglePinned() {
     const next = !skill.pinned;
     try {
@@ -587,6 +618,16 @@ export function SkillRow({
               )}
             </Button>
           )}
+          <Button
+            size="icon"
+            variant="ghost"
+            className="h-8 w-8 shrink-0"
+            disabled={duplicateSkillMutation.isPending}
+            onClick={handleOpenDuplicate}
+            title="复制为新技能"
+          >
+            <CopyIcon className="size-3.5" />
+          </Button>
           {canManage && (
             <Button
               size="icon"
@@ -600,6 +641,43 @@ export function SkillRow({
           )}
         </ItemActions>
       </Item>
+      <Dialog open={duplicateOpen} onOpenChange={setDuplicateOpen}>
+        <DialogContent>
+          <DialogHeader>
+            <DialogTitle>复制技能</DialogTitle>
+            <DialogDescription>
+              将「{desensitize(skill.name)}」复制为一个属于你的新技能。请输入新名称（仅小写字母、数字、- 或 _）。
+            </DialogDescription>
+          </DialogHeader>
+          <Input
+            value={duplicateName}
+            onChange={(e) => setDuplicateName(e.currentTarget.value)}
+            placeholder="new-skill-name"
+            autoFocus
+            onKeyDown={(e) => {
+              if (e.key === "Enter") {
+                e.preventDefault();
+                void handleDuplicate();
+              }
+            }}
+          />
+          <DialogFooter>
+            <Button
+              variant="outline"
+              onClick={() => setDuplicateOpen(false)}
+              disabled={duplicateSkillMutation.isPending}
+            >
+              {t.common.cancel}
+            </Button>
+            <Button
+              onClick={() => void handleDuplicate()}
+              disabled={duplicateSkillMutation.isPending}
+            >
+              {duplicateSkillMutation.isPending ? t.common.loading : "复制"}
+            </Button>
+          </DialogFooter>
+        </DialogContent>
+      </Dialog>
       <Dialog open={confirmDeleteOpen} onOpenChange={setConfirmDeleteOpen}>
         <DialogContent>
           <DialogHeader>