refactor: 兑换机制改为一图章一奖品并引入库存

- 废弃 RedemptionRule（集 N 换 1），新增 Prize 表与 Stamp 1:1 关联
- Redemption 记录直接绑定到 stampId + prizeId + prizeName 快照
- 兑换事务用 updateMany + stock>0 条件作乐观锁
- 兑换后保留 Collection 记录，图章持续彩色点亮并标记"已兑换"
- 用户端入口改为点击已收集图章弹出兑换，库存为 0 时按钮禁用
- 管理后台删除 /admin/rules，奖品编辑嵌入 StampForm

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/web/src/pages/AlbumPage.tsx

@@ -1,6 +1,6 @@
 import { useState, useEffect } from "react";
 import { useNavigate } from "react-router-dom";
-import type { StampWithStatus, RedemptionRuleInfo, RedemptionRecord } from "@stamp/shared";
+import type { StampWithStatus, RedemptionRecord } from "@stamp/shared";
 import { apiFetch } from "../lib/api";
 import { useAuth } from "../lib/auth";
 import StampGrid from "../components/StampGrid";
@@ -11,27 +11,25 @@ export default function AlbumPage() {
   const navigate = useNavigate();
   const { user, isLoading: authLoading } = useAuth();
   const [stamps, setStamps] = useState<StampWithStatus[]>([]);
-  const [rules, setRules] = useState<RedemptionRuleInfo[]>([]);
   const [history, setHistory] = useState<RedemptionRecord[]>([]);
   const [loading, setLoading] = useState(true);
-  const [showRedeem, setShowRedeem] = useState(false);
+  const [selectedStampId, setSelectedStampId] = useState<string | null>(null);
   const [showRegister, setShowRegister] = useState(false);
 
   const collectedCount = stamps.filter((s) => s.collected).length;
+  const selectedStamp = selectedStampId ? stamps.find((s) => s.id === selectedStampId) ?? null : null;
 
   const fetchData = async () => {
     setLoading(true);
     try {
-      const [stampsData, rulesData] = await Promise.all([
-        apiFetch<StampWithStatus[]>("/stamps"),
-        apiFetch<RedemptionRuleInfo[]>("/redemption/rules"),
-      ]);
+      const stampsData = await apiFetch<StampWithStatus[]>("/stamps");
       setStamps(stampsData);
-      setRules(rulesData);
 
       if (user) {
         const historyData = await apiFetch<RedemptionRecord[]>("/redemption/history");
         setHistory(historyData);
+      } else {
+        setHistory([]);
       }
     } catch {
       // Stamps endpoint works without auth
@@ -44,20 +42,21 @@ export default function AlbumPage() {
     if (!authLoading) fetchData();
   }, [authLoading, user]);
 
-  const handleRedeem = async (ruleId: string) => {
+  const handleRedeem = async (stampId: string) => {
     await apiFetch("/redemption/redeem", {
       method: "POST",
-      body: JSON.stringify({ ruleId }),
+      body: JSON.stringify({ stampId }),
     });
     await fetchData();
   };
 
-  const handleRedeemClick = () => {
+  const handleStampClick = (stamp: StampWithStatus) => {
     if (!user) {
       setShowRegister(true);
       return;
     }
-    setShowRedeem(true);
+    if (!stamp.collected) return;
+    setSelectedStampId(stamp.id);
   };
 
   if (loading || authLoading) {
@@ -108,40 +107,18 @@ export default function AlbumPage() {
             style={{ width: stamps.length ? `${(collectedCount / stamps.length) * 100}%` : "0%" }}
           />
         </div>
+        {collectedCount > 0 && (
+          <p className="mt-3 text-[11px] text-[var(--text-muted)] leading-relaxed">
+            点击已点亮的图章，即可兑换对应奖品
+          </p>
+        )}
       </div>
 
       {/* Stamp Grid */}
       <div className="px-4 pb-6">
-        <StampGrid stamps={stamps} />
+        <StampGrid stamps={stamps} onStampClick={handleStampClick} />
       </div>
 
-      {/* Redeem Section */}
-      {rules.length > 0 && (() => {
-        const availableCount = rules.filter((r) => collectedCount >= r.threshold).length;
-        const canRedeem = availableCount > 0;
-        return (
-          <div className="px-6 pb-6">
-            <button
-              onClick={handleRedeemClick}
-              disabled={!canRedeem}
-              className="w-full py-3.5 rounded-xl text-sm font-medium transition-all disabled:cursor-not-allowed flex items-center justify-center gap-2"
-              style={{
-                backgroundColor: canRedeem ? "var(--jade)" : "var(--border-muted)",
-                color: canRedeem ? "white" : "var(--text-muted)",
-                boxShadow: canRedeem ? "0 2px 8px rgba(45,106,79,0.25)" : "none",
-              }}
-            >
-              <span>{canRedeem ? "兑换奖品" : "继续收集以解锁奖品"}</span>
-              {canRedeem && (
-                <span className="text-xs px-2 py-0.5 rounded-full bg-white/20">
-                  {availableCount} 个可兑换
-                </span>
-              )}
-            </button>
-          </div>
-        );
-      })()}
-
       {/* Redemption History */}
       {history.length > 0 && (
         <div className="px-6 pb-8">
@@ -149,13 +126,13 @@ export default function AlbumPage() {
           <div className="space-y-2">
             {history.map((r) => (
               <div key={r.id} className="flex items-center justify-between py-2 px-3 bg-white/60 rounded-lg">
-                <div>
-                  <p className="text-sm text-[var(--text-primary)]">{r.ruleName}</p>
+                <div className="min-w-0">
+                  <p className="text-sm text-[var(--text-primary)] truncate">{r.prizeName}</p>
                   <p className="text-xs text-[var(--text-muted)]">
-                    {new Date(r.redeemedAt).toLocaleDateString("zh-CN")}
+                    {r.stampName} · {new Date(r.redeemedAt).toLocaleDateString("zh-CN")}
                   </p>
                 </div>
-                <span className="text-xs text-[var(--jade)]">已兑换</span>
+                <span className="text-xs text-[var(--jade)] shrink-0 ml-3">已兑换</span>
               </div>
             ))}
           </div>
@@ -163,12 +140,11 @@ export default function AlbumPage() {
       )}
 
       {/* Modals */}
-      {showRedeem && (
+      {selectedStamp && (
         <RedeemModal
-          rules={rules}
-          collectedCount={collectedCount}
+          stamp={selectedStamp}
           onRedeem={handleRedeem}
-          onClose={() => setShowRedeem(false)}
+          onClose={() => setSelectedStampId(null)}
         />
       )}