phase: 20.49 COMPLETE; 20.50 Flow+String minimal reps; 20.51 selfhost v0/v1 minimal (Option A/B); hv1-inline binop/unop/copy; docs + run_all + CURRENT_TASK -> 21.0

local_tests/test_zero_copy_simple.hako

@@ -0,0 +1,53 @@
+// 🧪 Zero-copy Detection Simple Test - Phase 10 Feature Verification
+// Testing BufferBox.is_shared_with() and share_reference() APIs
+
+static box Main {
+    init { console }
+    
+    main() {
+        me.console = new ConsoleBox()
+        me.console.log("🧪 Phase 10: Zero-copy Detection Test")
+        
+        // Test 1: Create two separate buffers (should NOT be shared)
+        me.console.log("\n=== Test 1: Separate buffers ===")
+        local buffer1 = new BufferBox()
+        local buffer2 = new BufferBox()
+        
+        buffer1.write("Hello World")
+        buffer2.write("Different Data")
+        
+        local is_shared_separate = buffer1.is_shared_with(buffer2)
+        me.console.log("Separate buffers shared: " + is_shared_separate)
+        
+        // Test 2: Create shared reference (SHOULD be shared)  
+        me.console.log("\n=== Test 2: Shared reference ===")
+        local buffer3 = new BufferBox()
+        buffer3.write("Shared Data Test")
+        
+        local shared_buffer = buffer3.share_reference(buffer3)
+        local is_shared_ref = buffer3.is_shared_with(shared_buffer)
+        me.console.log("Shared reference detection: " + is_shared_ref)
+        
+        // Test 3: Memory footprint monitoring
+        me.console.log("\n=== Test 3: Memory footprint ===")
+        local memory_size = buffer3.memory_footprint()
+        me.console.log("Buffer3 memory footprint: " + memory_size + " bytes")
+        
+        // Test 4: Zero-copy behavior simulation
+        me.console.log("\n=== Test 4: Zero-copy simulation ===")
+        local original_buffer = new BufferBox()
+        original_buffer.write("Large data for zero-copy test")
+        
+        local zero_copy_buffer = original_buffer.share_reference(original_buffer)
+        local zero_copy_result = original_buffer.is_shared_with(zero_copy_buffer)
+        
+        if (zero_copy_result.toString() == "true") {
+            me.console.log("✅ Zero-copy achieved! Memory sharing successful")
+        } else {
+            me.console.log("❌ Zero-copy failed! Unnecessary data copying detected")
+        }
+        
+        me.console.log("\n🎉 Phase 10 Zero-copy API Test Complete!")
+        return "Zero-copy test finished"
+    }
+}