fix(cloud-frontend,cloud-shared): remove mainnet chain + allow x-steward-tenant CORS header

- Remove Ethereum mainnet from wagmi chains in StewardWalletProviders to
  stop spurious Alchemy 429 floods on page load (mainnet not needed for
  BSC payments or SIWE signing)
- Add X-Steward-Tenant to CORS_ALLOW_HEADER_NAMES so Railway Steward
  proxy stops rejecting the header in preflight responses

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

Author: Shaw

packages/cloud-frontend/src/pages/login/steward-wallet-providers.tsx

@@ -15,7 +15,7 @@ import {
 } from "@solana/wallet-adapter-wallets";
 import { useMemo } from "react";
 import { http, WagmiProvider } from "wagmi";
-import { base, bsc, mainnet } from "wagmi/chains";
+import { base, bsc } from "wagmi/chains";
 
 const DEFAULT_SOLANA_RPC_URL = "https://api.mainnet-beta.solana.com";
 const FALLBACK_WALLETCONNECT_PROJECT_ID = "YOUR_WC_PROJECT_ID";
@@ -49,11 +49,8 @@ export function StewardWalletProviders({
           "Sign in to chat with your Eliza Cloud agent and manage your account",
         appUrl,
         projectId: walletConnectProjectId,
-        chains: [mainnet, base, bsc],
+        chains: [base, bsc],
         transports: {
-          [mainnet.id]: alchemyKey
-            ? http(`https://eth-mainnet.g.alchemy.com/v2/${alchemyKey}`)
-            : http("https://eth.publicnode.com"),
           [base.id]: alchemyKey
             ? http(`https://base-mainnet.g.alchemy.com/v2/${alchemyKey}`)
             : http("https://base-rpc.publicnode.com"),

packages/cloud-shared/src/lib/cors-constants.ts

@@ -30,6 +30,7 @@ export const CORS_ALLOW_HEADER_NAMES = [
   "X-PAYMENT",
   "X-PAYMENT-RESPONSE",
   "X-PAYMENT-STATUS",
+  "X-Steward-Tenant",
 ] as const;
 
 export const CORS_ALLOW_HEADERS = CORS_ALLOW_HEADER_NAMES.join(", ");