feat(cloud-frontend): real chain brand marks on earnings network dropdown

Replaces the colored-emoji placeholders (🔵🟣⬛🟡) on the Dashboard ▸
Earnings ▸ Redemption Network dropdown with @web3icons/react branded
SVG marks. The BNB Chain row in particular now uses the official BNB
Smart Chain logo via NetworkBinanceSmartChain instead of a generic
yellow circle.

All four entries swapped at once so the row is visually consistent:
- Base    → NetworkBase
- Solana  → TokenSOL
- Ethereum→ NetworkEthereum
- BNB     → NetworkBinanceSmartChain

The icons render at size={16} to align with the existing text-sm row.

Other parts of the audit (no code changes needed):
- The login EVM/Solana button is already on @web3icons/react (commit
  5c7cf08).
- No hardcoded BNB-yellow hex codes (#F0B90B, #FCD535) live in source
  outside DESIGN.md's documentation palette.
- The legacy "Binance Smart Chain" name only appears once in agent
  prompt content, contextually correct ("formerly Binance Smart
  Chain"). All UI / payments / payout code uses the current "BNB
  Smart Chain" / "BNB Chain" names.
- Network display names are consistent: payments use "BNB Smart Chain"
  (specific chain id 56) and dashboards use "BNB Chain" (umbrella
  brand) — both are valid current names per BNB Chain's 2022 rename.

Author: Shaw

packages/cloud-frontend/src/dashboard/earnings/_components/earnings-page-client.tsx

@@ -39,7 +39,11 @@ import {
   TrendingUp,
   Wallet,
 } from "lucide-react";
-import { useCallback, useEffect, useState } from "react";
+import NetworkBase from "@web3icons/react/icons/networks/NetworkBase";
+import NetworkBinanceSmartChain from "@web3icons/react/icons/networks/NetworkBinanceSmartChain";
+import NetworkEthereum from "@web3icons/react/icons/networks/NetworkEthereum";
+import TokenSOL from "@web3icons/react/icons/tokens/TokenSOL";
+import { type ReactNode, useCallback, useEffect, useState } from "react";
 import { toast } from "sonner";
 
 interface BalanceData {
@@ -111,11 +115,36 @@ interface SystemStatus {
   message?: string;
 }
 
-const NETWORKS = [
-  { value: "base", label: "Base", icon: "🔵" },
-  { value: "solana", label: "Solana", icon: "🟣" },
-  { value: "ethereum", label: "Ethereum", icon: "⬛" },
-  { value: "bnb", label: "BNB Chain", icon: "🟡" },
+// Real brand marks via @web3icons/react `variant="branded"` (the official
+// multi-color logos, not single-color stencils or emoji placeholders).
+// Network icons stay at 16px to align with the surrounding text-sm label.
+const NETWORKS: Array<{ value: string; label: string; icon: ReactNode }> = [
+  {
+    value: "base",
+    label: "Base",
+    icon: <NetworkBase variant="branded" size={16} aria-hidden="true" />,
+  },
+  {
+    value: "solana",
+    label: "Solana",
+    icon: <TokenSOL variant="branded" size={16} aria-hidden="true" />,
+  },
+  {
+    value: "ethereum",
+    label: "Ethereum",
+    icon: <NetworkEthereum variant="branded" size={16} aria-hidden="true" />,
+  },
+  {
+    value: "bnb",
+    label: "BNB Chain",
+    icon: (
+      <NetworkBinanceSmartChain
+        variant="branded"
+        size={16}
+        aria-hidden="true"
+      />
+    ),
+  },
 ];
 
 const SOURCE_ICONS = {