feat(firmware): validate configuration and migrate sensor-driven flight APIs

Validate configuration through its owning schemas and keep board
declarations separate from shared F722 resource ownership. Bound USB
transitions, isolate transport failures and retain restart-only activation.

Migrate navigation and flight consumers with the sensor and schema
contracts. Require explicit installation data and synchronous output
authority; board motor outputs remain inhibited.

Validation: assembled-prefix host tests, strict Clippy, platform/USB tests
and both ARM release builds. Final-source coverage and scoped Miri/Kani
evidence are retained separately from hardware qualification.

firmware/platforms/stm32f7/examples/mpu_dual_uart.rs

@@ -0,0 +1,38 @@
+#![cfg_attr(target_os = "none", no_std)]
+#![cfg_attr(target_os = "none", no_main)]
+#[cfg(target_os = "none")]
+mod support;
+#[cfg(target_os = "none")]
+mod target {
+    use platform_stm32f7::kaptan_ports::PortCatalog;
+    use platform_stm32f7::*;
+    pub struct Board;
+    impl F7Board for Board {
+        type UserConfig = super::support::UserConfig;
+        type ImmutableConfig = F722ImmutableConfig<Mpu6000Spi1>;
+        const FACTORY_USER_CONFIG: Self::UserConfig = super::support::FACTORY;
+        const IMMUTABLE_CONFIG: Self::ImmutableConfig = F722ImmutableConfig {
+            name: "synthetic MPU dual UART",
+            service_hz: 100,
+            hardware: F722Hardware::new(
+                Mpu6000Spi1 {
+                    mount: ImuMount::BodyAligned,
+                    config: Mpu6000Config {
+                        accelerometer: AccelerometerRange::PlusMinus4G,
+                        gyroscope: GyroscopeRange::PlusMinus500DegreesPerSecond,
+                        digital_low_pass_filter: DigitalLowPassFilter::Bandwidth42Hz,
+                        sample_rate_divider: 9,
+                    },
+                },
+                SerialInventory::new(&super::support::Both::DESCRIPTORS),
+                StatusLed::ActiveHighPa13,
+                VerticalSensor::None,
+                MotorPins::Four,
+            ),
+        };
+    }
+}
+#[cfg(target_os = "none")]
+platform_stm32f7::flight_firmware!(crate::target::Board);
+#[cfg(not(target_os = "none"))]
+fn main() {}