docs(i18n): PX4 guide translations (Crowdin) - zh-CN (#26851)

Co-authored-by: Crowdin Bot <support+bot@crowdin.com>

docs/zh/sensor/barometer.md

@@ -65,7 +65,7 @@ This calibration is controlled by the [SENS_BAR_AUTOCAL](../advanced_config/para
 The algorithm monitors GNSS quality, collects altitude differences over a 2-second filtered window, and verifies stability within 4m tolerance.
 Once stable, it uses binary search to calculate pressure offsets that align baro altitude with GNSS altitude (0.1m precision), then applies the offset to all sensors and saves the parameters.
 
-备注：
+Notes:
 
 - **EKF Independence**: GNSS-baro calibration operates independently of EKF2 altitude fusion settings.
 - **Execution Timing**: Calibration runs even when [EKF2_GPS_CTRL](../advanced_config/parameter_reference.md#EKF2_GPS_CTRL) altitude fusion is disabled.

docs/zh/sensor/optical_flow.md

@@ -34,6 +34,12 @@ The information is written to the corresponding uORB topics: [DistanceSensor](..
 | Right            | - X             |
 | Left             | + X             |
 
+:::info
+The integrated flow values are **angular measurements** (radians) representing rotation of the image about the sensor's body axes using the right-hand convention.
+They are _not_ translational displacements along those axes, which is why forward vehicle movement (along X) appears in the Y flow axis, and rightward movement (along Y) appears in the X flow axis.
+Specifically, forward movement causes the ground image to rotate about the Y axis (+ Y), while rightward movement causes a negative rotation about the X axis (- X).
+:::
+
 Sensor data from the optical flow device is fused with other velocity data sources.
 The approach used for fusing sensor data and any offsets from the center of the vehicle must be configured in the [estimator](#estimators).