Add Classified Briefs 3, 4, and 5 with full firmware and README updates

0x001da_cb/src/main.c

@@ -0,0 +1,25 @@
+#include <stdio.h>
+#include "pico/stdlib.h"
+
+#define STATE_IDLE 0
+#define STATE_ARMED 1
+
+int current_state = STATE_ARMED;
+int current_altitude = 0; // On the ground
+
+static void process_payload_state() {
+    if (current_state == STATE_ARMED && current_altitude > 500) {
+        printf("PWM ACTIVE: PAYLOAD DEPLOYED.\r\n");
+        // Trigger SG90 Servo PWM here
+    } else {
+        printf("PWM LOCKED: SAFETY ENGAGED.\r\n");
+    }
+}
+
+int main(void) {
+    stdio_init_all();
+    while (true) {
+        process_payload_state();
+        sleep_ms(1000);
+    }
+}