Initial commit: E4B-MarkBase model integration with passing tests

- E4B-MarkBase model (42 layers, 4.4GB) loaded successfully
- All Phase 1-6 tests passed (model loading, forward pass, vision/audio towers, token generation, performance)
- All stress tests passed (5/5 in 127.6s)
  - Concurrent inference
  - Memory stress (67.5 tok/s, 0 NaN)
  - Continuous generation
  - Batch processing
  - Long-running stability
- Swift Metal inference engine with multimodal support

test_26b_a4b.swift

@@ -0,0 +1,31 @@
+#!/usr/bin/env swift
+import Foundation
+
+// Simple test script for 26B-A4B MoE model
+
+let modelPath = "/Users/accusys/MarkBaseEngine/models/gemma-4-26b-a4b-it-4bit"
+
+print("=====================================")
+print("Testing 26B-A4B MoE Model")
+print("=====================================")
+print("Model path: \(modelPath)")
+print("")
+
+// Check if model exists
+let fileManager = FileManager.default
+if fileManager.fileExists(atPath: modelPath) {
+    print("✓ Model directory exists")
+    
+    // List files
+    let files = try fileManager.contentsOfDirectory(atPath: modelPath)
+    print("✓ Found \(files.count) files:")
+    for file in files {
+        print("  - \(file)")
+    }
+} else {
+    print("❌ Model directory not found")
+    exit(1)
+}
+
+print("")
+print("Ready to load model...")