style: Fix coding style violations in nuttx-apps

Fix various coding style issues including:
- Case statement formatting
- Include placement and ordering
- Whitespace issues
- Long line formatting
- Bracket alignment

Affected modules:
- audioutils, examples, include
- netutils, system

Signed-off-by: Huang Qi <huangqi3@xiaomi.com>

examples/elf/tests/struct/struct_main.c

@@ -35,7 +35,7 @@
 
 const struct struct_dummy_s dummy_struct =
 {
-   DUMMY_SCALAR_VALUE3
+  DUMMY_SCALAR_VALUE3
 };
 
 int dummy_scalar = DUMMY_SCALAR_VALUE2;