Added Global Mutex for SD IOPS, and changed OTA to write directly to Flash

vesper/vesper.ino

@@ -122,6 +122,7 @@
 // ═══════════════════════════════════════════════════════════════════════════════════
 // CUSTOM CLASSES - Include Custom Classes and Functions
 // ═══════════════════════════════════════════════════════════════════════════════════
+#include "src/SDCardMutex/SDCardMutex.hpp"  // ⚠️ MUST be included before any SD-using classes
 #include "src/ConfigManager/ConfigManager.hpp"
 #include "src/FileManager/FileManager.hpp"
 #include "src/TimeKeeper/TimeKeeper.hpp"
@@ -206,6 +207,15 @@ void setup()
 	SPI.begin(hwConfig.ethSpiSck, hwConfig.ethSpiMiso, hwConfig.ethSpiMosi);
   delay(50);
 
+	// 🔒 CRITICAL: Initialize SD Card Mutex BEFORE any SD operations
+	// This prevents concurrent SD access from multiple FreeRTOS tasks
+	if (!SDCardMutex::getInstance().begin()) {
+		Serial.println("❌ FATAL: Failed to initialize SD card mutex!");
+		Serial.println("   System cannot continue safely - entering infinite loop");
+		while(1) { delay(1000); }  // Halt system - unsafe to proceed
+	}
+	Serial.println("✅ SD card mutex initialized");
+
 	// Initialize Configuration (loads factory identity from NVS + user settings from SD)
 	configManager.begin();