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/components/PostInteractPanels.tsx

@@ -17,6 +17,7 @@ import {
 } from "@/lib/api";
 import { toast } from "@/lib/toast";
 import Avatar from "@/components/Avatar";
+import { useAllowComments } from "@/components/CommentsPolicyProvider";
 
 export default function PostInteractPanels({
   postId,
@@ -177,6 +178,7 @@ function DeadlineCountdown({
 
 /** 正文下方的问答状态卡（未解决 / 仅标记已解决）；有采纳答案时改用 AcceptedAnswerCard */
 export function QuestionStatusCard({ postId, state }: { postId: number; state: QuestionState }) {
+  const allowComments = useAllowComments();
   const router = useRouter();
   const [busy, setBusy] = useState(false);
 
@@ -241,7 +243,7 @@ export function QuestionStatusCard({ postId, state }: { postId: number; state: Q
 
       <p className="j13-typed-meta">
         {state.solved
-          ? state.accepted_comment_id
+          ? state.accepted_comment_id && allowComments
             ? (
                 <>
                   已采纳{" "}
@@ -255,7 +257,9 @@ export function QuestionStatusCard({ postId, state }: { postId: number; state: Q
                 </>
               )
             : "作者已标记为已解决"
-          : "可在评论旁采纳答案，或手动标记已解决"}
+          : allowComments
+            ? "可在评论旁采纳答案，或手动标记已解决"
+            : "可由作者标记为已解决"}
       </p>
 
       <div className="j13-typed-foot">
@@ -466,6 +470,7 @@ function PollPanel({
 }
 
 function BountyPanel({ state }: { postId: number; state: BountyState }) {
+  const allowComments = useAllowComments();
   const statusBadge = state.accepted_comment_id
     ? { cls: "badge-status badge-status-solved", label: "已采纳" }
     : state.expired || state.refunded
@@ -507,7 +512,7 @@ function BountyPanel({ state }: { postId: number; state: BountyState }) {
       <p className="j13-typed-meta">
         <span className="j13-bounty-points tabular-nums">{state.points} 积分</span>
         {bodyHint ? ` · ${bodyHint}` : null}
-        {state.can_accept ? " · 在评论旁点击「采纳」发放积分" : null}
+        {state.can_accept && allowComments ? " · 在评论旁点击「采纳」发放积分" : null}
       </p>
 
       {!state.accepted_comment_id && state.ends_at ? (
@@ -518,7 +523,7 @@ function BountyPanel({ state }: { postId: number; state: BountyState }) {
         />
       ) : null}
 
-      {state.accepted_comment_id > 0 && (
+      {allowComments && state.accepted_comment_id > 0 && (
         <p className="j13-typed-meta">
           已采纳{" "}
           <a