style: enforce coding standard — headers, @brief on #define, Doxygen on statics, remove _ prefix, max 8 lines per function

0x0001_hello-world/0x0001_hello-world.c

@@ -1,9 +1,46 @@
+/**
+ * @file 0x0001_hello-world.c
+ * @brief Hello World: print a greeting over UART in an infinite loop
+ * @author Kevin Thomas
+ * @date 2025
+ *
+ * MIT License
+ *
+ * Copyright (c) 2025 Kevin Thomas
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * -----------------------------------------------------------------------------
+ *
+ * Demonstrates the minimal "hello, world" program on the Raspberry Pi Pico 2.
+ * Initializes stdio over UART and prints a greeting in an infinite loop.
+ *
+ * Wiring:
+ *   No external wiring required (USB serial).
+ */
+
 #include <stdio.h>
 #include "pico/stdlib.h"
 
 int main(void) {
     stdio_init_all();
-
-    while (true)
+    while (true) {
         printf("hello, world\r\n");
+    }
 }