feat(drivers): validate bounded IMU FIFO acquisition

Drain bounded MPU6000 and ICM-42688 FIFO batches. Publish the latest
validated sample only after overflow checks. Reject invalid drains.

Validation: driver, sensor and platform tests plus both ARM release builds
from a fresh build directory.

firmware/libs/kaptan-drivers/src/icm42688/error.rs

@@ -27,7 +27,19 @@ pub enum Error<BusError> {
     /// The bus stayed busy for the pending operation's 20 ms admission budget.
     #[kaptan_error(id = 5107)]
     AdmissionTimeout,
-    /// No acquisition was requested within two output periods plus 10 ms.
+    /// No checked, nonempty batch arrived within two output periods plus 10 ms.
     #[kaptan_error(id = 5108)]
     DataReadyTimeout,
+    /// FIFO full status or the lost-packet counter reports missing records.
+    #[kaptan_error(id = 5109)]
+    FifoOverflow,
+    /// The reported FIFO count exceeds the configured packet capacity.
+    #[kaptan_error(id = 5110)]
+    FifoCount(u16),
+    /// A packet has an invalid header, sensor code, or timestamp order.
+    #[kaptan_error(id = 5111)]
+    FifoPacket,
+    /// The sensor reset after its configuration had completed.
+    #[kaptan_error(id = 5112)]
+    UnexpectedReset,
 }