Fix deploy_account.ts and restore isTestnet() for testnet compatibility

The merge mangled deploy_account.ts — restore testnet bridging logic
with next's API changes (NO_FROM instead of AztecAddress.ZERO).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: critesjosh

config/config.ts

@@ -67,6 +67,10 @@ export class ConfigManager {
     return this.config.network;
   }
 
+  public isTestnet(): boolean {
+    return this.config.environment === 'testnet';
+  }
+
   public isLocalNetwork(): boolean {
     return this.config.environment === 'local';
   }

src/utils/deploy_account.ts

@@ -56,7 +56,7 @@ export async function deploySchnorrAccount(wallet?: EmbeddedWallet): Promise<Acc
             logger.info('✅ Fee juice claim ready for account deployment');
         }
     } else {
-        // Devnet/local: use sponsored FPC
+        // Local: use sponsored FPC
         logger.info('💰 Setting up sponsored fee payment for account deployment...');
         const sponsoredFPC = await getSponsoredFPCInstance();
         logger.info(`💰 Sponsored FPC instance obtained at: ${sponsoredFPC.address}`);
@@ -76,8 +76,8 @@ export async function deploySchnorrAccount(wallet?: EmbeddedWallet): Promise<Acc
     // Deploy account
     await deployMethod.send({
         from: NO_FROM,
-        fee: { paymentMethod: sponsoredPaymentMethod },
-        wait: { timeout: 120 },
+        wait: { timeout: timeouts.deployTimeout },
+        ...(paymentMethod ? { fee: { paymentMethod } } : {}),
     });
 
     logger.info(`✅ Account deployment transaction successful!`);