fix: configure RPC endpoints and CSP for Cloudflare deployment

  - Add explicit RPC URLs to wagmi config with publicnode.com fallbacks
  - Support env vars for custom RPC endpoints (NEXT_PUBLIC_*_RPC_URL)
  - Add Content-Security-Policy header allowing HTTPS connections
  - Fix BSC RPC URL in .env.example (was testnet, now mainnet)

Author: fbsobreira

.env.example

@@ -5,5 +5,5 @@ NEXT_PUBLIC_KLEVER_API_URL=https://api.mainnet.klever.org
 # For production, consider using dedicated RPC providers for better reliability
 NEXT_PUBLIC_ETHEREUM_RPC_URL=https://ethereum-rpc.publicnode.com
 NEXT_PUBLIC_POLYGON_RPC_URL=https://polygon-bor-rpc.publicnode.com
-NEXT_PUBLIC_BSC_RPC_URL=https://bsc-testnet-rpc.publicnode.com
+NEXT_PUBLIC_BSC_RPC_URL=https://bsc-rpc.publicnode.com
 NEXT_PUBLIC_ARBITRUM_RPC_URL=https://arbitrum-one-rpc.publicnode.com

next.config.ts

@@ -34,6 +34,10 @@ const nextConfig: NextConfig = {
             key: "X-DNS-Prefetch-Control",
             value: "on",
           },
+          {
+            key: "Content-Security-Policy",
+            value: "default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-inline'; img-src 'self' data: https:; connect-src 'self' https:; font-src 'self' data:;",
+          },
         ],
       },
     ];

src/config/wagmi.ts

@@ -4,10 +4,10 @@ import { mainnet, polygon, bsc, arbitrum } from "wagmi/chains";
 export const config = createConfig({
   chains: [mainnet, polygon, bsc, arbitrum],
   transports: {
-    [mainnet.id]: http(),
-    [polygon.id]: http(),
-    [bsc.id]: http(),
-    [arbitrum.id]: http(),
+    [mainnet.id]: http(process.env.NEXT_PUBLIC_ETHEREUM_RPC_URL || "https://ethereum-rpc.publicnode.com"),
+    [polygon.id]: http(process.env.NEXT_PUBLIC_POLYGON_RPC_URL || "https://polygon-bor-rpc.publicnode.com"),
+    [bsc.id]: http(process.env.NEXT_PUBLIC_BSC_RPC_URL || "https://bsc-rpc.publicnode.com"),
+    [arbitrum.id]: http(process.env.NEXT_PUBLIC_ARBITRUM_RPC_URL || "https://arbitrum-one-rpc.publicnode.com"),
   },
 });