docs: add Interoperability section to README with gomobile example

Author: xaionaro@dx.center

README.md

@@ -1627,6 +1627,88 @@ bridging. Writing CGo from scratch duplicates this work and lacks the
 automated test coverage this project maintains.
 -->
 
+## Interoperability with standard packages
+
+All handle types expose `UintPtr() uintptr` and `NewXFromUintPtr(uintptr)` methods alongside the existing `Pointer()`/`NewXFromPointer()` pair. This enables interop with Go packages that represent native Android handles as `uintptr` — including `golang.org/x/mobile`, `gioui.org`, and `github.com/xlab/android-go`.
+
+For generic code, all handles satisfy the `handle.NativeHandle` interface:
+
+```go
+import "github.com/AndroidGoLab/ndk/handle"
+
+func logHandle(h handle.NativeHandle) {
+    log.Printf("native handle: 0x%x", h.UintPtr())
+}
+```
+
+EGL types (`EGLDisplay`, `EGLContext`, etc.) are `unsafe.Pointer` aliases and use free functions instead: `egl.EGLDisplayToUintPtr(d)` / `egl.EGLDisplayFromUintPtr(p)`.
+
+<details>
+<summary>gomobile bind</summary>
+
+`gomobile bind` does not support `unsafe.Pointer` or `uintptr` in exported APIs. Transport native handles as `int64` (Java `long`) and convert inside Go:
+
+```go
+package sensorbridge
+
+import "github.com/AndroidGoLab/ndk/sensor"
+
+// Bridge wraps an ASensorManager for cross-language use.
+// Unexported fields are invisible to Java/Kotlin.
+type Bridge struct {
+	mgr *sensor.Manager
+}
+
+// NewBridge creates a Bridge from a raw ASensorManager* passed as int64
+// (Java long). gomobile bind does not support unsafe.Pointer or uintptr,
+// so native handles must be transported as int64.
+func NewBridge(managerHandle int64) *Bridge {
+	return &Bridge{
+		mgr: sensor.NewManagerFromUintPtr(uintptr(managerHandle)),
+	}
+}
+
+// Handle returns the underlying ASensorManager* as int64 for passing
+// back to Java/JNI code.
+func (b *Bridge) Handle() int64 {
+	return int64(b.mgr.UintPtr())
+}
+
+// AccelerometerName returns the name of the default accelerometer,
+// or empty string if unavailable.
+func (b *Bridge) AccelerometerName() string {
+	s := b.mgr.DefaultSensor(sensor.Accelerometer)
+	if s.UintPtr() == 0 {
+		return ""
+	}
+	return s.Name()
+}
+
+// SensorName returns the name of a sensor by its Android type code,
+// or empty string if the sensor is not available.
+func (b *Bridge) SensorName(sensorType int32) string {
+	s := b.mgr.DefaultSensor(sensor.Type(sensorType))
+	if s.UintPtr() == 0 {
+		return ""
+	}
+	return s.Name()
+}
+```
+
+Build AAR: `gomobile bind -target=android -androidapi=35 ./examples/gomobile/sensorbridge`
+
+Java usage:
+
+```java
+long ptr = nativeGetSensorManager(); // from JNI
+Bridge bridge = Sensorbridge.newBridge(ptr);
+String name = bridge.accelerometerName();
+```
+
+See [`examples/gomobile/sensorbridge/`](examples/gomobile/sensorbridge/) for the complete buildable example.
+
+</details>
+
 ## FAQ
 
 **Q: Why NativeActivity instead of GameActivity?**