feat: 全站评论开关，并统一后台表单控件

关闭评论后前台隐藏评论能力；外观/设置/公告改用 AdminField 与 Stepper。

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/app/admin/appearance/AppearanceAdmin.tsx

@@ -5,14 +5,22 @@ import { useRouter } from "next/navigation";
 import {
   Palette,
   Check,
+  Code2,
   Loader2,
   Save,
   Undo2,
   RotateCcw,
   Pipette,
+  Sparkles,
 } from "lucide-react";
-import { AdminPageHeader, AdminSection } from "@/components/admin";
-import { apiUpdateSiteSettings } from "@/lib/api";
+import {
+  AdminPageHeader,
+  AdminSection,
+  AdminSettingRow,
+  AdminStepper,
+  AdminSwitch,
+} from "@/components/admin";
+import { apiUpdateSiteSettings, type PublicSettings } from "@/lib/api";
 import { toast } from "@/lib/toast";
 import {
   ACCENT_PRESETS,
@@ -23,13 +31,27 @@ import {
   normalizeHex,
 } from "@/lib/theme";
 
-// 后台「外观设置」：站点主题色预设 + 自定义取色 + 实时预览。
-// 修改时立即对整页实时预览（仅本地），保存后才写库并对所有用户生效。
-export default function AppearanceAdmin({ initialAccent }: { initialAccent: string }) {
+// 后台「外观设置」：主题色、代码块折叠与界面动画。
+// 主题色修改时立即对整页实时预览（仅本地），保存后才写库并对所有用户生效。
+export default function AppearanceAdmin({ initial }: { initial: PublicSettings }) {
   const router = useRouter();
+  const initialAccent = initial.accent || "";
   // 已保存值：空串=内置默认（靛蓝）
-  const [savedHex, setSavedHex] = useState(initialAccent || "");
+  const [savedHex, setSavedHex] = useState(initialAccent);
   const [draft, setDraft] = useState(initialAccent || DEFAULT_ACCENT);
+  const [codeAutoFold, setCodeAutoFold] = useState(initial.code_block_auto_fold !== false);
+  const [foldLines, setFoldLines] = useState(
+    Number.isFinite(initial.code_block_fold_lines) ? initial.code_block_fold_lines : 5
+  );
+  const [togglingFold, setTogglingFold] = useState(false);
+  const [savingFoldLines, setSavingFoldLines] = useState(false);
+  const [uiAnimations, setUiAnimations] = useState(initial.ui_animations !== false);
+  const [animCodeFold, setAnimCodeFold] = useState(initial.anim_code_fold !== false);
+  const [animSmoothScroll, setAnimSmoothScroll] = useState(
+    initial.anim_smooth_scroll !== false
+  );
+  const [animChrome, setAnimChrome] = useState(initial.anim_chrome !== false);
+  const [togglingMotion, setTogglingMotion] = useState(false);
   const [saving, setSaving] = useState(false);
   const savedRef = useRef(savedHex);
   savedRef.current = savedHex;
@@ -76,12 +98,79 @@ export default function AppearanceAdmin({ initialAccent }: { initialAccent: stri
     applyAccentTheme(savedHex || null);
   };
 
+  const toggleCodeFold = async () => {
+    if (togglingFold) return;
+    const next = !codeAutoFold;
+    setTogglingFold(true);
+    try {
+      const res = await apiUpdateSiteSettings({ code_block_auto_fold: next });
+      setCodeAutoFold(res.code_block_auto_fold);
+      toast(
+        res.code_block_auto_fold
+          ? `已开启代码块自动折叠（超过 ${res.code_block_fold_lines} 行）`
+          : "已关闭代码块自动折叠",
+        "ok"
+      );
+    } catch (e) {
+      toast(e instanceof Error ? e.message : "保存失败");
+    } finally {
+      setTogglingFold(false);
+    }
+  };
+
+  const saveFoldLines = async () => {
+    if (savingFoldLines) return;
+    const raw = Math.round(Number(foldLines));
+    const n = Number.isFinite(raw) ? Math.max(0, Math.min(100, raw)) : 5;
+    setSavingFoldLines(true);
+    try {
+      const res = await apiUpdateSiteSettings({ code_block_fold_lines: n });
+      setFoldLines(res.code_block_fold_lines);
+      toast(
+        res.code_block_fold_lines === 0
+          ? "折叠预览已设为 0 行（无预览）"
+          : `折叠阈值已设为超过 ${res.code_block_fold_lines} 行`,
+        "ok"
+      );
+    } catch (e) {
+      toast(e instanceof Error ? e.message : "保存失败");
+    } finally {
+      setSavingFoldLines(false);
+    }
+  };
+
+  const toggleMotionField = async (
+    key: "ui_animations" | "anim_code_fold" | "anim_smooth_scroll" | "anim_chrome",
+    next: boolean
+  ) => {
+    if (togglingMotion) return;
+    setTogglingMotion(true);
+    try {
+      const res = await apiUpdateSiteSettings({ [key]: next });
+      setUiAnimations(res.ui_animations);
+      setAnimCodeFold(res.anim_code_fold);
+      setAnimSmoothScroll(res.anim_smooth_scroll);
+      setAnimChrome(res.anim_chrome);
+      const labels: Record<typeof key, [string, string]> = {
+        ui_animations: ["已开启界面动画", "已关闭界面动画（全站减少动态效果）"],
+        anim_code_fold: ["已开启代码折叠动画", "已关闭代码折叠动画"],
+        anim_smooth_scroll: ["已开启平滑滚动", "已关闭平滑滚动"],
+        anim_chrome: ["已开启装饰入场动画", "已关闭装饰入场动画"],
+      };
+      toast(next ? labels[key][0] : labels[key][1], "ok");
+    } catch (e) {
+      toast(e instanceof Error ? e.message : "保存失败");
+    } finally {
+      setTogglingMotion(false);
+    }
+  };
+
   return (
     <div className="max-w-3xl">
       <AdminPageHeader
         icon={Palette}
         title="外观设置"
-        description="配置站点主题色，全站按钮、链接、选中态会统一联动"
+        description="配置站点主题色、代码块折叠与界面动画"
       />
 
       <div className="flex flex-col gap-4 mb-6">
@@ -157,15 +246,13 @@ export default function AppearanceAdmin({ initialAccent }: { initialAccent: stri
             </label>
             <div className="flex flex-col gap-1">
               <div
-                className="flex items-center rounded-[var(--r-sm)] border bg-[var(--panel)] px-3 h-11 font-mono text-[14px] w-40"
-                style={{ borderColor: invalid ? "var(--danger)" : "var(--line-2)" }}
+                className={`admin-field-shell px-3 h-11 font-mono text-[14px] w-40${invalid ? " is-invalid" : ""}`}
               >
                 <span style={{ color: "var(--ink-3)" }}>#</span>
                 <input
                   value={draft.startsWith("#") ? draft.slice(1) : draft}
                   onChange={(e) => setDraft("#" + e.target.value.replace(/[^0-9a-fA-F#]/g, ""))}
-                  className="flex-1 min-w-0 bg-transparent outline-none ml-1 uppercase"
-                  style={{ color: "var(--ink)" }}
+                  className="admin-field-input flex-1 min-w-0 px-0 py-0 ml-1 uppercase"
                   maxLength={7}
                   spellCheck={false}
                   aria-label="主题色 HEX 值"
@@ -253,6 +340,131 @@ export default function AppearanceAdmin({ initialAccent }: { initialAccent: stri
             </div>
           </div>
         </AdminSection>
+
+        <AdminSettingRow
+          title={
+            <>
+              <Code2 size={15} /> 代码块自动折叠
+            </>
+          }
+          description="开启后，帖子与评论中超过阈值行数的 Markdown 代码块默认折叠，读者可点「展开全部」。关闭则始终完整展示。"
+          control={
+            <AdminSwitch
+              checked={codeAutoFold}
+              disabled={togglingFold}
+              onChange={() => void toggleCodeFold()}
+              label="代码块自动折叠"
+            />
+          }
+        >
+          {codeAutoFold ? (
+            <>
+              <label className="field-label" htmlFor="fold-lines">
+                折叠行数阈值
+              </label>
+              <p className="meta text-[12.5px] mb-2.5 leading-relaxed">
+                代码块行数超过该值时折叠；折叠后约露出同样行数。设为 0 表示无预览。范围 0–100，默认 5。
+              </p>
+              <div className="flex flex-wrap items-center gap-2.5">
+                <AdminStepper
+                  id="fold-lines"
+                  value={foldLines}
+                  onChange={setFoldLines}
+                  min={0}
+                  max={100}
+                  unit="行"
+                  ariaLabel="折叠行数阈值"
+                  disabled={savingFoldLines}
+                />
+                <button
+                  type="button"
+                  className="btn btn-line btn-sm"
+                  disabled={savingFoldLines}
+                  onClick={() => void saveFoldLines()}
+                >
+                  {savingFoldLines ? (
+                    <Loader2 size={14} className="animate-spin" />
+                  ) : (
+                    <Save size={14} />
+                  )}
+                  保存
+                </button>
+              </div>
+            </>
+          ) : null}
+        </AdminSettingRow>
+
+        <AdminSettingRow
+          title={
+            <>
+              <Sparkles size={15} /> 界面动画
+            </>
+          }
+          description="总开关关闭后全站即时切换（等同减少动态效果）。系统若已开启「减少动态效果」，始终优先生效。开启总开关后可细调子项。"
+          control={
+            <AdminSwitch
+              checked={uiAnimations}
+              disabled={togglingMotion}
+              onChange={() => void toggleMotionField("ui_animations", !uiAnimations)}
+              label="界面动画总开关"
+            />
+          }
+        >
+          {uiAnimations ? (
+            <div className="space-y-4">
+              <div className="flex items-start justify-between gap-4 flex-wrap">
+                <div className="min-w-0 flex-1">
+                  <p className="text-[13.5px] font-medium" style={{ color: "var(--ink)" }}>
+                    代码折叠动画
+                  </p>
+                  <p className="meta text-[12.5px] mt-0.5 leading-relaxed">
+                    代码块展开/收起的高度过渡与跟滚。
+                  </p>
+                </div>
+                <AdminSwitch
+                  checked={animCodeFold}
+                  disabled={togglingMotion}
+                  onChange={() => void toggleMotionField("anim_code_fold", !animCodeFold)}
+                  label="代码折叠动画"
+                />
+              </div>
+              <div className="flex items-start justify-between gap-4 flex-wrap">
+                <div className="min-w-0 flex-1">
+                  <p className="text-[13.5px] font-medium" style={{ color: "var(--ink)" }}>
+                    平滑滚动
+                  </p>
+                  <p className="meta text-[12.5px] mt-0.5 leading-relaxed">
+                    目录跳转、回顶、新内容提示等 scroll 行为。
+                  </p>
+                </div>
+                <AdminSwitch
+                  checked={animSmoothScroll}
+                  disabled={togglingMotion}
+                  onChange={() =>
+                    void toggleMotionField("anim_smooth_scroll", !animSmoothScroll)
+                  }
+                  label="平滑滚动"
+                />
+              </div>
+              <div className="flex items-start justify-between gap-4 flex-wrap">
+                <div className="min-w-0 flex-1">
+                  <p className="text-[13.5px] font-medium" style={{ color: "var(--ink)" }}>
+                    装饰入场
+                  </p>
+                  <p className="meta text-[12.5px] mt-0.5 leading-relaxed">
+                    列表入场、Toast、点赞弹出、在线脉冲等装饰性动画。
+                  </p>
+                </div>
+                <AdminSwitch
+                  checked={animChrome}
+                  disabled={togglingMotion}
+                  onChange={() => void toggleMotionField("anim_chrome", !animChrome)}
+                  label="装饰入场"
+                />
+              </div>
+            </div>
+          ) : null}
+        </AdminSettingRow>
       </div>
 
       <div className="flex items-center justify-between gap-3 sticky bottom-5 panel !p-3.5 pl-5 z-10">