fix(cover): 系统模板点击'套用'走新建路径；403/401错误提示增强

1. CoverSettingsModal: 系统模板按钮从'编辑'改为'套用'，语义更清晰
2. useSharedCover.handleEditTemplate: 系统模板传入时自动清掉id+is_system，让handleSaveTemplate走create分支而非update，避免触发后端'系统模板不可修改'403
3. useSharedCover错误处理增强：提取axios response的detail/message信息，区分401（登录过期）/403（权限不足）/其他错误，提示更明确
4. 所有CRUD操作的console.error补充status和detail信息，便于后续问题定位

apps/web/src/components/cover/useSharedCover.ts

@@ -86,8 +86,27 @@ export function useSharedCover(opts: UseSharedCoverOptions): UseSharedCoverRetur
       }))
       setTemplates(list)
     } catch (err) {
-      console.error("[SharedCover] 加载封面模板失败:", err)
-      setTemplatesError("加载模板失败，请稍后重试")
+      const axiosErr = err as {
+        response?: {
+          status?: number
+          data?: { detail?: string; message?: string; error?: { message?: string } }
+        }
+        message?: string
+      }
+      const status = axiosErr?.response?.status
+      const detail =
+        axiosErr?.response?.data?.detail ||
+        axiosErr?.response?.data?.message ||
+        axiosErr?.response?.data?.error?.message ||
+        axiosErr?.message
+      console.error("[SharedCover] 加载封面模板失败:", err, "status=", status, "detail=", detail)
+      if (status === 401) {
+        setTemplatesError("登录已过期，请刷新页面重新登录")
+      } else if (status === 403) {
+        setTemplatesError(detail ? "权限不足：" + detail : "无权限访问封面模板")
+      } else {
+        setTemplatesError("加载模板失败：" + (detail || "请稍后重试"))
+      }
     } finally {
       setTemplatesLoading(false)
     }
@@ -104,7 +123,12 @@ export function useSharedCover(opts: UseSharedCoverOptions): UseSharedCoverRetur
   }, [])
 
   const handleEditTemplate = useCallback((tpl: CoverTemplate) => {
-    setEditingTemplate(tpl)
+    // 系统模板不能直接修改：清除 id/is_system，让 onSave 走 create 分支（基于系统模板新建自定义模板）
+    if (tpl.is_system) {
+      setEditingTemplate({ ...tpl, id: "", name: tpl.name + "(自定义)", is_system: false })
+    } else {
+      setEditingTemplate(tpl)
+    }
     setShowCoverEditor(true)
   }, [])
 
@@ -126,8 +150,25 @@ export function useSharedCover(opts: UseSharedCoverOptions): UseSharedCoverRetur
         }
         setShowCoverEditor(false)
       } catch (err) {
-        console.error("[SharedCover] 保存模板失败:", err)
-        message.error("保存模板失败，请稍后重试")
+        const axiosErr = err as {
+          response?: {
+            status?: number
+            data?: { detail?: string; message?: string; error?: { message?: string } }
+          }
+          message?: string
+        }
+        const status = axiosErr?.response?.status
+        const detail =
+          axiosErr?.response?.data?.detail ||
+          axiosErr?.response?.data?.message ||
+          axiosErr?.response?.data?.error?.message ||
+          axiosErr?.message
+        console.error("[SharedCover] 保存模板失败:", err, "status=", status, "detail=", detail)
+        if (status === 403) {
+          message.error("保存失败（权限不足）：" + (detail || "无权操作该模板"))
+        } else {
+          message.error("保存模板失败：" + (detail || "请稍后重试"))
+        }
       }
     },
     [templates],
@@ -142,8 +183,25 @@ export function useSharedCover(opts: UseSharedCoverOptions): UseSharedCoverRetur
           setSelectedTemplateId("default")
         }
       } catch (err) {
-        console.error("[SharedCover] 删除模板失败:", err)
-        message.error("删除模板失败，请稍后重试")
+        const axiosErr = err as {
+          response?: {
+            status?: number
+            data?: { detail?: string; message?: string; error?: { message?: string } }
+          }
+          message?: string
+        }
+        const status = axiosErr?.response?.status
+        const detail =
+          axiosErr?.response?.data?.detail ||
+          axiosErr?.response?.data?.message ||
+          axiosErr?.response?.data?.error?.message ||
+          axiosErr?.message
+        console.error("[SharedCover] 删除模板失败:", err, "status=", status, "detail=", detail)
+        if (status === 403) {
+          message.error("删除失败（权限不足）：" + (detail || "无权操作该模板"))
+        } else {
+          message.error("删除模板失败：" + (detail || "请稍后重试"))
+        }
       }
     },
     [selectedTemplateId],

apps/web/src/pages/generate/components/cover-settings/CoverSettingsModal.tsx

@@ -110,8 +110,13 @@ const CoverSettingsModal: React.FC<CoverSettingsModalProps> = ({
                     {tpl.is_system && <span className="xx-cover-template-badge">✨ 系统</span>}
                   </div>
                   <div className="xx-cover-template-actions" onClick={(e) => e.stopPropagation()}>
-                    <Button buttonType="ghost" buttonSize="sm" onClick={() => onEditTemplate(tpl)}>
-                      编辑
+                    <Button
+                      buttonType="ghost"
+                      buttonSize="sm"
+                      onClick={() => onEditTemplate(tpl)}
+                      title={tpl.is_system ? "基于此模板新建自定义模板" : "编辑模板"}
+                    >
+                      {tpl.is_system ? "套用" : "编辑"}
                     </Button>
                     {!tpl.is_system && (
                       <Button