feat(public): 首页移除品牌/产地筛选，合格档案数移至页脚

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

public-frontend/src/App.tsx

@@ -1,9 +1,10 @@
-import { useState } from "react";
+import { useEffect, useState } from "react";
 import { Boxes, Search, PlusCircle, Code2 } from "lucide-react";
 import Home from "./components/Home";
 import ProductView from "./components/ProductView";
 import Contribute from "./components/Contribute";
 import ApiDocs from "./components/ApiDocs";
+import { api } from "./api";
 
 type View =
   | { name: "home" }
@@ -13,6 +14,14 @@ type View =
 
 export default function App() {
   const [view, setView] = useState<View>({ name: "home" });
+  const [qualified, setQualified] = useState<number | null>(null);
+
+  useEffect(() => {
+    api
+      .stats()
+      .then((s) => setQualified(s.qualified))
+      .catch(() => setQualified(null));
+  }, []);
 
   return (
     <div className="min-h-full flex flex-col">
@@ -73,6 +82,15 @@ export default function App() {
 
       <footer className="border-t bg-white">
         <div className="max-w-5xl mx-auto px-4 py-4 text-xs text-gray-400 leading-relaxed">
+          {qualified != null && (
+            <div className="mb-2 text-gray-500">
+              目前已收录
+              <span className="mx-1 font-semibold text-emerald-600">
+                {qualified.toLocaleString()}
+              </span>
+              条合格商品档案
+            </div>
+          )}
           天工商品档案公共仓 是公益性「商品事实库」，仅收录客观商品信息（条码、品牌、品类、营养、官方建议零售价快照等），不含任何购买/交易功能。
           公众投稿须经人工审核后方可收纳。
           <button onClick={() => setView({ name: "api" })} className="ml-1 text-emerald-600 hover:underline">