feat: complete M3 Web UI Enhancement milestone with include/exclude cards, fuzzy matching, mobile responsive design, and performance optimization

- Include/exclude cards feature complete with 300+ card knowledge base and intelligent fuzzy matching
- Enhanced visual validation with warning icons and performance benchmarks (100% pass rate)
- Mobile responsive design with bottom-floating controls, two-column layout, and horizontal scroll prevention
- Dark theme confirmation modal for fuzzy matches with card preview and alternatives
- Dual architecture support for web UI staging system and CLI direct build paths
- All M3 checklist items completed: fuzzy match modal, enhanced algorithm, summary panel, mobile responsive, Playwright tests

test_fuzzy_modal.py

@@ -0,0 +1,123 @@
+#!/usr/bin/env python3
+"""
+Test script to verify fuzzy match confirmation modal functionality.
+"""
+
+import sys
+import os
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), 'code'))
+
+import requests
+import json
+
+def test_fuzzy_match_confirmation():
+    """Test that fuzzy matching returns confirmation_needed items for low confidence matches."""
+    print("🔍 Testing fuzzy match confirmation modal backend...")
+    
+    # Test with a typo that should trigger confirmation
+    test_data = {
+        'include_cards': 'Lighning',  # Worse typo to trigger confirmation
+        'exclude_cards': '',
+        'commander': 'Alesha, Who Smiles at Death',  # Valid commander with red identity
+        'enforcement_mode': 'warn',
+        'allow_illegal': 'false',
+        'fuzzy_matching': 'true'
+    }
+    
+    try:
+        response = requests.post('http://localhost:8080/build/validate/include_exclude', data=test_data)
+        
+        if response.status_code != 200:
+            print(f"❌ Request failed with status {response.status_code}")
+            return False
+            
+        data = response.json()
+        
+        # Check if confirmation_needed is populated
+        if 'confirmation_needed' not in data:
+            print("❌ No confirmation_needed field in response")
+            return False
+            
+        if not data['confirmation_needed']:
+            print("❌ confirmation_needed is empty")
+            print(f"Response: {json.dumps(data, indent=2)}")
+            return False
+            
+        confirmation = data['confirmation_needed'][0]
+        expected_fields = ['input', 'suggestions', 'confidence', 'type']
+        
+        for field in expected_fields:
+            if field not in confirmation:
+                print(f"❌ Missing field '{field}' in confirmation")
+                return False
+        
+        print(f"✅ Fuzzy match confirmation working!")
+        print(f"   Input: {confirmation['input']}")
+        print(f"   Suggestions: {confirmation['suggestions']}")
+        print(f"   Confidence: {confirmation['confidence']:.2%}")
+        print(f"   Type: {confirmation['type']}")
+        
+        return True
+        
+    except Exception as e:
+        print(f"❌ Test failed with error: {e}")
+        return False
+
+def test_exact_match_no_confirmation():
+    """Test that exact matches don't trigger confirmation."""
+    print("\n🎯 Testing exact match (no confirmation)...")
+    
+    test_data = {
+        'include_cards': 'Lightning Bolt',  # Exact match
+        'exclude_cards': '',
+        'commander': 'Alesha, Who Smiles at Death',  # Valid commander with red identity
+        'enforcement_mode': 'warn',
+        'allow_illegal': 'false',
+        'fuzzy_matching': 'true'
+    }
+    
+    try:
+        response = requests.post('http://localhost:8080/build/validate/include_exclude', data=test_data)
+        
+        if response.status_code != 200:
+            print(f"❌ Request failed with status {response.status_code}")
+            return False
+            
+        data = response.json()
+        
+        # Should not have confirmation_needed for exact match
+        if data.get('confirmation_needed'):
+            print(f"❌ Exact match should not trigger confirmation: {data['confirmation_needed']}")
+            return False
+            
+        # Should have legal includes
+        if not data.get('includes', {}).get('legal'):
+            print("❌ Exact match should be in legal includes")
+            print(f"Response: {json.dumps(data, indent=2)}")
+            return False
+            
+        print("✅ Exact match correctly bypasses confirmation!")
+        return True
+        
+    except Exception as e:
+        print(f"❌ Test failed with error: {e}")
+        return False
+
+if __name__ == "__main__":
+    print("🧪 Testing Fuzzy Match Confirmation Modal")
+    print("=" * 50)
+    
+    test1_pass = test_fuzzy_match_confirmation()
+    test2_pass = test_exact_match_no_confirmation()
+    
+    print("\n📋 Test Summary:")
+    print(f"   Fuzzy confirmation: {'✅ PASS' if test1_pass else '❌ FAIL'}")
+    print(f"   Exact match: {'✅ PASS' if test2_pass else '❌ FAIL'}")
+    
+    if test1_pass and test2_pass:
+        print("\n🎉 All fuzzy match tests passed!")
+        print("💡 Modal functionality ready for user testing")
+    else:
+        print("\n🔧 Some tests failed - check implementation")
+        
+    exit(0 if test1_pass and test2_pass else 1)