feat: add PCARS 1 & 2 UDP telemetry parser (port 5606)

- Auto-detect PCARS1 (1367-byte V1) vs PCARS2 (559-byte V2) packet format
- Parse speed, RPM, gear, inputs, tyres, engine temps, damage, weather
- Map PCARS-specific fields to TelemetryFrame (oil/water temp, damage, etc.)
- Add FeedSource::Pcars + 16 PCARS-specific Option fields to TelemetryFrame
- Port 5606 as optional bind-listen feed (like Telemetry Tool)
- 5 new unit tests for PCARS parser (32 total)
- Shared binary_utils module for all parsers

src/binary_utils.rs

@@ -41,6 +41,22 @@ pub fn read_i16(data: &[u8], offset: usize) -> i16 {
     i16::from_le_bytes(buf)
 }
 
+/// Read a little-endian `u16` from the data at the given offset.
+/// Returns 0 if the offset is out of bounds (safe fallback for malformed packets).
+pub fn read_u16(data: &[u8], offset: usize) -> u16 {
+    let buf: [u8; 2] = data
+        .get(offset..offset + 2)
+        .and_then(|s| s.try_into().ok())
+        .unwrap_or([0u8; 2]);
+    u16::from_le_bytes(buf)
+}
+
+/// Read a signed `i8` from the data at the given offset.
+/// Returns 0 if the offset is out of bounds.
+pub fn read_i8(data: &[u8], offset: usize) -> i8 {
+    data.get(offset).map(|&b| b as i8).unwrap_or(0)
+}
+
 /// Read a little-endian `f32` from the data at the given offset.
 /// Returns 0.0 if the offset is out of bounds (safe fallback for malformed packets).
 pub fn read_f32(data: &[u8], offset: usize) -> f32 {