fix: resolve 7 code review issues from v0.4.x

- Fix KSUDP clutch field reading fuel at offset 59 (KSUDP has no clutch input)
- Replace Notify with watch::channel for reliable shutdown (no missed wakeups)
- Deduplicate read_u16 from parser_pcars into shared binary_utils
- Remove dead Display impl for FeedSource
- Remove unused read_i8 helper from binary_utils
- Change Vec<Instant> to [Instant; 50] in FeedState (eliminate heap alloc)
- Cache rarely-changing strings by driver_id in Telemetry Tool parser

src/telemetry_frame.rs

@@ -3,8 +3,6 @@
 //! Both the KSUDP (port 9996) and Telemetry Tool (port 10101) parsers produce
 //! `TelemetryFrame` instances from their raw binary data.
 
-use std::fmt;
-
 /// Identifies which feed source produced this frame.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum FeedSource {
@@ -242,13 +240,3 @@ impl TelemetryFrame {
         }
     }
 }
-
-impl fmt::Display for FeedSource {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            FeedSource::Ksudp => write!(f, "KSUDP"),
-            FeedSource::TelemetryTool => write!(f, "Telemetry Tool"),
-            FeedSource::Pcars => write!(f, "PCARS"),
-        }
-    }
-}