feat: Add VM statistics and fix compilation errors for plugin tests

- Add VM instruction statistics (--vm-stats, --vm-stats-json)
- Fix missing fields in ast.rs test code (public_fields, private_fields)
- Add CliConfig fields for VM statistics
- Enable TLV debug logging in plugin_loader_v2
- Successfully test FileBox handle passing and HTTP plugin creation

🤖 Generated with [Claude Code](https://claude.ai/code)

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

local_tests/test_return_42.nyash

@@ -1,5 +1,2 @@
-static box Main {
-    main() {
-        return 42
-    }
-}
+// Simple return test
+return 42