Add 0x0026a custom AES-128-CMAC secure bootloader, Week 11a notebook, and README links

0x0026a_custom-bootloader/bootloader/include/boot.h

@@ -0,0 +1,45 @@
+/**
+ * @file boot.h
+ * @brief Secure boot console and application handoff helpers.
+ * @author Kevin Thomas
+ * @date 2026
+ *
+ * MIT License
+ * Copyright (c) 2026 Kevin Thomas
+ */
+
+#ifndef BOOT_H
+#define BOOT_H
+
+#include "manifest.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Bring up the debug console and print the boot banner.
+ * @param void No parameters.
+ * @return void No return value.
+ */
+void boot_init(void);
+
+/**
+ * @brief Print a boot failure reason and idle forever.
+ * @param reason Null-terminated message describing the failure.
+ * @return void Does not return.
+ */
+void boot_halt(const char *reason);
+
+/**
+ * @brief Announce the verified image and jump to its reset vector.
+ * @param manifest Pointer to the validated manifest.
+ * @return void Does not return.
+ */
+void boot_launch(const fw_manifest_t *manifest);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // BOOT_H