feat: Add enhanced EXI viewer with XML decode capability

- Implement complete CurrentDemandReq/CurrentDemandRes parsing (24 total fields)
- Add enhanced_exi_viewer.c with detailed message analysis
- Support -decode option for clean XML output (file-ready format)
- Enable ISO1, ISO2, DIN codec support in build configuration
- Fix C99 compatibility issues in makefiles (change -ansi to -std=c99)
- Create test utilities for hex string to EXI conversion
- Generate test files: test3.exi (CurrentDemandRes), test4.exi (CurrentDemandReq)

Features:
* Dual output modes: detailed analysis (default) vs XML (-decode)
* Complete V2G message type detection and parsing
* Session ID display in hex and ASCII formats
* Voltage/current/power readings with proper units
* All optional fields and status flags supported

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

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

Debug/src/transport/subdir.mk

@@ -0,0 +1,24 @@
+################################################################################
+# Automatically-generated file. Do not edit!
+################################################################################
+
+# Add inputs and outputs from these tool invocations to the build variables 
+C_SRCS += \
+../src/transport/v2gtp.c 
+
+OBJS += \
+./src/transport/v2gtp.o 
+
+C_DEPS += \
+./src/transport/v2gtp.d 
+
+
+# Each subdirectory must supply rules for building sources it contributes
+src/transport/%.o: ../src/transport/%.c
+	@echo 'Building file: $<'
+	@echo 'Invoking: GCC C Compiler'
+	gcc -I"../src/codec" -I"../src/din" -I"../src/iso1" -I"../src/iso2" -I"../src/xmldsig" -I"../src/appHandshake" -I"../src/transport" -I"../src/test" -O0 -g3 -Wall -c -fmessage-length=0 -std=c99 -MMD -MP -MF"$(@:%.o=%.d)" -MT"$(@:%.o=%.d)" -o "$@" "$<"
+	@echo 'Finished building: $<'
+	@echo ' '
+
+

Debug/src/transport/v2gtp.d

@@ -0,0 +1,3 @@
+src/transport/v2gtp.d: ../src/transport/v2gtp.c ../src/transport/v2gtp.h
+
+../src/transport/v2gtp.h: