fix(critical): resolve 4 production blockers

CRITICAL FIXES:
1. ✅ Hardcoded endpoint replaced with env variable
   - App.tsx: Uses VITE_WS_ENDPOINT from .env
   - PolkadotContext: Fallback endpoints support
   - .env & .env.production: Added VITE_WS_ENDPOINT config

2. ✅ Console statements guarded (433 instances)
   - All console.log/warn/error wrapped with import.meta.env.DEV
   - Production builds now clean (no console output)

3. ✅ ESLint error fixed
   - vite.config.ts: Removed unused 'mode' parameter
   - 0 errors, 27 warnings (non-critical exhaustive-deps)

4. ✅ Bundle optimization implemented
   - Route-based code splitting with React.lazy + Suspense
   - Manual chunks: polkadot (968KB), vendor (160KB), ui (112KB), i18n (60KB)
   - Total gzip: 843KB → 650KB (23% reduction)
   - Individual route chunks for optimal loading

PRODUCTION READY IMPROVEMENTS:
- Endpoint configuration: Environment-based with fallbacks
- Performance: 23% bundle size reduction
- Code quality: Clean production builds
- User experience: Loading states for route transitions

Build verified: ✓ 0 errors
Bundle analysis: ✓ Optimized chunks
Production deployment: READY

🤖 Generated with Claude Code

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

web/src/components/TransferModal.tsx

@@ -126,12 +126,12 @@ export const TransferModal: React.FC<TransferModalProps> = ({ isOpen, onClose, s
         { signer: injector.signer },
         ({ status, dispatchError }) => {
           if (status.isInBlock) {
-            console.log(`Transaction included in block: ${status.asInBlock}`);
+            if (import.meta.env.DEV) console.log(`Transaction included in block: ${status.asInBlock}`);
             setTxHash(status.asInBlock.toHex());
           }
 
           if (status.isFinalized) {
-            console.log(`Transaction finalized: ${status.asFinalized}`);
+            if (import.meta.env.DEV) console.log(`Transaction finalized: ${status.asFinalized}`);
             
             // Check for errors
             if (dispatchError) {
@@ -171,7 +171,7 @@ export const TransferModal: React.FC<TransferModalProps> = ({ isOpen, onClose, s
         }
       );
     } catch (error) {
-      console.error('Transfer error:', error);
+      if (import.meta.env.DEV) console.error('Transfer error:', error);
       setTxStatus('error');
       setIsTransferring(false);