feat(wallet): swap CTA glyph to Figma 4414-12829 filled wallet icon

The 链接钱包 CTA was using the lucide outline Wallet icon. Replace it
with a local WalletIcon component built from the exact Figma path
(filled body, currentColor fill) so the icon paints in dark on the
yellow CTA, matching Figma's #08070C fill via the button's text-black
utility.

src/wallet/WalletButton.tsx

@@ -1,6 +1,7 @@
-import { Heart, Wallet } from "lucide-react";
+import { Heart } from "lucide-react";
 import { useEffect, useRef, useState } from "react";
 import { Link } from "react-router-dom";
+import { WalletIcon } from "../components/icons/WalletIcon";
 import { useI18n } from "../i18n";
 import { useLocalizedPath } from "../useLocalizedPath";
 import { shortenAddress, useWallet } from "./WalletProvider";
@@ -111,7 +112,7 @@ export function WalletButton({
         compact ? "w-full" : "min-w-[124px] shrink-0 whitespace-nowrap",
       ].join(" ")}
     >
-      <Wallet className="h-4 w-4" strokeWidth={2.5} aria-hidden />
+      <WalletIcon className="h-[18px] w-[18px]" />
       <span>
         {wallet.status === "loading" ? t("loading") : t("walletConnect")}
       </span>