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/parser_telemetry_tool.rs

@@ -104,6 +104,7 @@ pub fn parse_packet(data: &[u8]) -> Result<TelemetryToolPacket, TelemetryToolPar
 ///
 /// Avoids allocating a `Vec` for all drivers when only the local player's
 /// telemetry is needed.
+#[allow(dead_code)]
 pub fn parse_first_driver(data: &[u8]) -> Result<TelemetryFrame, TelemetryToolParseError> {
     if data.is_empty() {
         return Err(TelemetryToolParseError::TooShort { actual: 0, needed: 1 });
@@ -125,8 +126,56 @@ pub fn parse_first_driver(data: &[u8]) -> Result<TelemetryFrame, TelemetryToolPa
     parse_driver(&payload[..DRIVER_STRUCT_SIZE])
 }
 
+/// Parse only the first driver, skipping rarely-changing string fields.
+///
+/// Returns a tuple of (frame, raw_driver_id). Strings can be populated
+/// from a cache keyed by `raw_driver_id`.
+pub fn parse_first_driver_no_strings(data: &[u8]) -> Result<(TelemetryFrame, u32), TelemetryToolParseError> {
+    if data.is_empty() {
+        return Err(TelemetryToolParseError::TooShort { actual: 0, needed: 1 });
+    }
+
+    let packet_type = data[0];
+    if packet_type != PACKET_TYPE_TELEMETRY {
+        return Err(TelemetryToolParseError::UnknownPacketType { got: packet_type });
+    }
+
+    let payload = &data[1..];
+    if payload.len() < DRIVER_STRUCT_SIZE {
+        return Err(TelemetryToolParseError::TooShort {
+            actual: data.len(),
+            needed: 1 + DRIVER_STRUCT_SIZE,
+        });
+    }
+
+    let driver_data = &payload[..DRIVER_STRUCT_SIZE];
+    let driver_id = read_u32(driver_data, 0);
+    let mut frame = parse_driver_core(driver_data)?;
+    frame.driver_id = Some(driver_id);
+    Ok((frame, driver_id))
+}
+
+pub const STRING_OFFSET_DRIVER_NAME: usize = 1 + 97;
+pub const STRING_LEN_DRIVER_NAME: usize = 33;
+pub const STRING_OFFSET_NATIONALITY: usize = 1 + 130;
+pub const STRING_LEN_NATIONALITY: usize = 4;
+pub const STRING_OFFSET_CAR_NAME: usize = 1 + 134;
+pub const STRING_LEN_CAR_NAME: usize = 33;
+pub const STRING_OFFSET_TYRE_COMPOUND: usize = 1 + 167;
+pub const STRING_LEN_TYRE_COMPOUND: usize = 10;
+
 /// Parse a single 357-byte driver structure.
 fn parse_driver(data: &[u8]) -> Result<TelemetryFrame, TelemetryToolParseError> {
+    let mut frame = parse_driver_core(data)?;
+    frame.driver_id = Some(read_u32(data, 0));
+    frame.driver_name = Some(read_string(data, 97, 33));
+    frame.nationality = Some(read_string(data, 130, 4));
+    frame.car_name = Some(read_string(data, 134, 33));
+    frame.tyre_compound = Some(read_string(data, 167, 10));
+    Ok(frame)
+}
+
+fn parse_driver_core(data: &[u8]) -> Result<TelemetryFrame, TelemetryToolParseError> {
     // Validation: check test_float at offset 93
     let test_float_val = read_f32(data, 93);
     if (test_float_val - TEST_FLOAT).abs() > 1.0 {
@@ -195,11 +244,6 @@ fn parse_driver(data: &[u8]) -> Result<TelemetryFrame, TelemetryToolParseError>
         tyre_slip: read_f32_4(data, 305),
 
         // Telemetry Tool-specific fields
-        driver_id: Some(read_u32(data, 0)),
-        driver_name: Some(read_string(data, 97, 33)),
-        nationality: Some(read_string(data, 130, 4)),
-        car_name: Some(read_string(data, 134, 33)),
-        tyre_compound: Some(read_string(data, 167, 10)),
         track_position: Some(read_i16(data, 67)),
         leaderboard_position: Some(read_i16(data, 69)),
         is_connected: Some(read_bool(data, 181)),