fix: use System.Number instead of LastRuntimeUpgrade in waitForChainReady

System.LastRuntimeUpgrade doesn't exist in bulletin runtime's typed API

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: x3c41a

examples/common.js

@@ -127,14 +127,10 @@ export async function waitForChainReady(typedApi, maxRetries = 10, retryDelayMs
 
     for (let attempt = 1; attempt <= maxRetries; attempt++) {
         try {
-            // Try multiple queries to ensure chain is fully synced
-            const [runtimeVersion, blockNumber] = await Promise.all([
-                typedApi.query.System.LastRuntimeUpgrade(),
-                typedApi.query.System.Number()
-            ]);
-            
+            // Query block number to verify chain is synced and responsive
+            const blockNumber = await typedApi.query.System.Number();
             const blockNum = blockNumber ?? 0;
-            console.log(`✅ Chain is ready! Block #${blockNum}, Runtime: ${runtimeVersion ? 'available' : 'checking...'}`);
+            console.log(`✅ Chain is ready! Block #${blockNum}`);
             return true;
         } catch (error) {
             if (attempt < maxRetries) {