refactor: move PipeWire initialization into a reusable helper function (#69)

Extract duplicated `pipewire::init()`, `MainLoopRc::new()`, and `ContextRc::new()` setup code from `pw_get_global_objects_thread`, `create_virtual_mic`, and `create_link` into a shared `setup_pipewire_context` helper in `src/utils/pipewire.rs`. Also ran codebase-wide linters to improve code quality.

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

src/bin/daemon.rs

@@ -42,10 +42,10 @@ async fn main() -> Result<(), Box<dyn Error>> {
     lock_file.lock()?;
 
     let socket_path = runtime_dir.join("daemon.sock");
-    if let Err(e) = fs::remove_file(&socket_path) {
-        if e.kind() != std::io::ErrorKind::NotFound {
-            return Err(e.into());
-        }
+    if let Err(e) = fs::remove_file(&socket_path)
+        && e.kind() != std::io::ErrorKind::NotFound
+    {
+        return Err(e.into());
     }
 
     let listener = UnixListener::bind(&socket_path)?;