fix: Resolve EXI encoding issues and enhance V2GDecoder functionality

- Fix critical EXI encoding error -109 (EXI_ERROR_UNKOWN_EVENT) by adding proper structure initialization
  * Added init_iso1BodyType() call before setting message type flags in XML parsing
  * Prevents garbage values in unused message type flags that caused wrong grammar paths

- Rename enhanced_exi_viewer to V2GDecoder for consistency
  * Updated build.bat to build V2GDecoder instead of enhanced_exi_viewer
  * Maintains all existing functionality with improved reliability

- Add comprehensive structure debugging capabilities
  * Created structure dump functions to output complete document state
  * Added struct_exi.txt and struct_xml.txt for comparing parsed vs original structures

- Enhance output formatting for encoding operations
  * Clean hex-only output for encoding mode (similar to XML decode mode)
  * Removed debug clutter for production use while preserving debugging code

- Add test infrastructure with minimal_test.xml for focused testing
  * Validates CurrentDemandReq message encoding with minimal required fields

- Improve encoder debugging with position tracking in iso1EXIDatatypesEncoder.c
  * Added debug points to track exact failure locations during encoding

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

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

struct_exi.txt

@@ -0,0 +1,46 @@
+=== ISO1 EXI Document Structure Dump ===
+
+V2G_Message_isUsed: 1
+
+--- Header ---
+SessionID.bytesLen: 8
+SessionID.bytes: 4142423030303831
+Notification_isUsed: 0
+Signature_isUsed: 0
+
+--- Body Message Type Flags ---
+AuthorizationReq_isUsed: 0
+AuthorizationRes_isUsed: 0
+BodyElement_isUsed: 0
+CableCheckReq_isUsed: 0
+CableCheckRes_isUsed: 0
+CertificateInstallationReq_isUsed: 0
+CertificateInstallationRes_isUsed: 0
+CertificateUpdateReq_isUsed: 0
+CertificateUpdateRes_isUsed: 0
+ChargeParameterDiscoveryReq_isUsed: 0
+ChargeParameterDiscoveryRes_isUsed: 0
+ChargingStatusReq_isUsed: 0
+ChargingStatusRes_isUsed: 0
+CurrentDemandReq_isUsed: 0
+CurrentDemandRes_isUsed: 1
+MeteringReceiptReq_isUsed: 0
+MeteringReceiptRes_isUsed: 0
+PaymentDetailsReq_isUsed: 0
+PaymentDetailsRes_isUsed: 0
+PaymentServiceSelectionReq_isUsed: 0
+PaymentServiceSelectionRes_isUsed: 0
+PowerDeliveryReq_isUsed: 0
+PowerDeliveryRes_isUsed: 0
+PreChargeReq_isUsed: 0
+PreChargeRes_isUsed: 0
+ServiceDetailReq_isUsed: 0
+ServiceDetailRes_isUsed: 0
+ServiceDiscoveryReq_isUsed: 0
+ServiceDiscoveryRes_isUsed: 0
+SessionSetupReq_isUsed: 0
+SessionSetupRes_isUsed: 0
+SessionStopReq_isUsed: 0
+SessionStopRes_isUsed: 0
+WeldingDetectionReq_isUsed: 0
+WeldingDetectionRes_isUsed: 0