🔧 Add #[allow(dead_code)] to unused items

- Suppress dead code warnings for utility functions, enums and traits not yet used in production
- Reorganize imports to follow module conventions (e.g., `DeviceIdentity` moved earlier in openhome_renderer.rs)
- Improve formatting of ClientMessage variants for readability
These changes prepare codebase groundwork without altering runtime behavior.

pmoaudio-ext/src/sinks/broadcast_pacing.rs

@@ -38,6 +38,7 @@ impl BroadcastPacer {
     }
 
     /// Reset the pacer clock (call when audio timestamp resets to 0).
+    #[allow(dead_code)]
     pub fn reset(&mut self) {
         self.start_time = Instant::now();
         trace!("{} broadcaster: pacer reset", self.label);

pmoaudio-ext/src/sinks/flac_frame_utils.rs

@@ -296,6 +296,7 @@ pub(crate) fn validate_frame_header_crc(data: &[u8], offset: usize) -> bool {
 /// keeping the data from the last sync code onward for the next iteration.
 ///
 /// We need at least 2 validated sync codes to identify one complete frame.
+#[allow(dead_code)]
 pub(crate) fn find_complete_frames_boundary(data: &[u8]) -> usize {
     if data.len() < 4 {
         return 0;