Add DFTE sources and tests

include/DeviceFrameworkTemplateEngineDebug.h

@@ -0,0 +1,121 @@
+#ifndef DEVICEFRAMEWORK_TEMPLATE_ENGINE_DEBUG_H
+#define DEVICEFRAMEWORK_TEMPLATE_ENGINE_DEBUG_H
+
+#include <Arduino.h>
+
+// ============================================================================
+// LOGGING INTERFACE - Framework Agnostic
+// ============================================================================
+
+/**
+ * Logging interface for the DeviceFramework Template Engine
+ * 
+ * This interface allows any logging system to be plugged into the template engine.
+ * The template engine itself remains completely framework-agnostic.
+ * 
+ * Usage:
+ * 1. Implement this interface with your preferred logging system
+ * 2. Call deviceFrameworkTemplateEngineEnableLogging() with your logger instance
+ * 3. All DFTE_LOG_* macros will then use your logger
+ * 
+ * Example:
+ *   class MyLogger : public DeviceFrameworkTemplateEngineLogger {
+ *       void error(const String& msg) override { // your logging logic }
+ *       void warn(const String& msg) override { // your logging logic }
+ *       void info(const String& msg) override { // your logging logic }
+ *       void debug(const String& msg) override { // your logging logic }
+ *   };
+ *   
+ *   MyLogger myLogger;
+ *   deviceFrameworkTemplateEngineEnableLogging(&myLogger);
+ */
+class DeviceFrameworkTemplateEngineLogger {
+public:
+    virtual void error(const String& msg) = 0;
+    virtual void warn(const String& msg) = 0;
+    virtual void info(const String& msg) = 0;
+    virtual void debug(const String& msg) = 0;
+    virtual ~DeviceFrameworkTemplateEngineLogger() {}
+};
+
+// Global logger pointer - set by user or defaults to nullptr (disabled)
+extern DeviceFrameworkTemplateEngineLogger* deviceFrameworkTemplateEngineLogger;
+
+// ============================================================================
+// LOGGING MACROS - NO-OPS BY DEFAULT
+// ============================================================================
+
+/**
+ * DeviceFramework Template Engine Logging System
+ * 
+ * LOGGING IS DISABLED BY DEFAULT - All macros are no-ops unless explicitly enabled
+ * 
+ * To enable logging:
+ * 1. Implement the DeviceFrameworkTemplateEngineLogger interface with your preferred logging system
+ * 2. Call deviceFrameworkTemplateEngineEnableLogging() with your logger instance
+ * 
+ * This design ensures:
+ * - Zero logging overhead by default
+ * - Complete framework decoupling
+ * - Flexible logging system integration
+ * - No build flags or conditional compilation needed
+ */
+
+// All logging macros are no-ops by default - zero overhead unless explicitly enabled
+#define DFTE_LOG_ERROR(msg) do { \
+    if (deviceFrameworkTemplateEngineLogger) { \
+        deviceFrameworkTemplateEngineLogger->error(msg); \
+    } \
+} while(0)
+
+#define DFTE_LOG_WARN(msg) do { \
+    if (deviceFrameworkTemplateEngineLogger) { \
+        deviceFrameworkTemplateEngineLogger->warn(msg); \
+    } \
+} while(0)
+
+#define DFTE_LOG_INFO(msg) do { \
+    if (deviceFrameworkTemplateEngineLogger) { \
+        deviceFrameworkTemplateEngineLogger->info(msg); \
+    } \
+} while(0)
+
+#define DFTE_LOG_DEBUG(msg) do { \
+    if (deviceFrameworkTemplateEngineLogger) { \
+        deviceFrameworkTemplateEngineLogger->debug(msg); \
+    } \
+} while(0)
+
+// ============================================================================
+// LOGGING CONFIGURATION FUNCTIONS
+// ============================================================================
+
+/**
+ * Enable logging with a custom logger implementation
+ * 
+ * @param logger Pointer to custom logger implementation
+ * @return true if logging was enabled, false if logger is null
+ */
+bool deviceFrameworkTemplateEngineEnableLogging(DeviceFrameworkTemplateEngineLogger* logger);
+
+/**
+ * Disable all logging
+ * Sets logger to nullptr, making all DFTE_LOG_* macros no-ops
+ */
+void deviceFrameworkTemplateEngineDisableLogging();
+
+/**
+ * Check if logging is currently enabled
+ * 
+ * @return true if logging is enabled, false if disabled
+ */
+bool deviceFrameworkTemplateEngineIsLoggingEnabled();
+
+/**
+ * Get current logger
+ * 
+ * @return Pointer to current logger or nullptr if disabled
+ */
+DeviceFrameworkTemplateEngineLogger* deviceFrameworkTemplateEngineGetLogger();
+
+#endif // DEVICEFRAMEWORK_TEMPLATE_ENGINE_DEBUG_H