refactor(firmware): centralize configuration and diagnostics

firmware/libs/kaptan-tx/src/lib.rs

@@ -44,6 +44,16 @@ pub enum EnqueueResult {
     BestEffortDropped,
 }
 
+impl EnqueueResult {
+    /// Whether the submitted frame remains represented by the queue.
+    pub const fn is_retained(self) -> bool {
+        matches!(
+            self,
+            Self::Enqueued | Self::ReplacedBestEffort | Self::ReplacedCritical
+        )
+    }
+}
+
 /// Result of attempting to begin a transfer.
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
 pub enum StartOutcome {