fix: Correct inverted Android stick Y axis and map the RX/RY right stick

[spydon]

Follow-up to #128, which fixed the same double inversion for the d-pad hat axis but left the analog sticks inconsistent with it. Also closes the second symptom reported in #123.

Stick Y axis was double inverted

gamepads_android's EventListener registers AXIS_Y, AXIS_RZ and AXIS_RY with invert = true, so a physical stick-up already arrives in Dart as +1.0. AndroidMapping.normalizeAxis negated it a second time:

if (axis == GamepadAxis.leftStickY || axis == GamepadAxis.rightStickY) {
  return [NormalizedAxis(axis, -value)];
}

The result was leftStickY = -1.0 for up on Android, while the same gesture gives +1.0 on iOS, macOS and Web. That contradicts the convention documented on GamepadAxis and PlatformMapping ("Left/Down = -1, Right/Up = +1"), so cross-platform game code moved the player in opposite directions.

After #128 the file also argued both ways: "EventListener already inverted it" for the hat axis, and the opposite three lines above for the sticks.

RX/RY right stick events were dropped

EventListener reports AXIS_RX and AXIS_RY (added in #111 for non-Xbox layouts such as the DJI RC Pro), but they were missing from _axisMap. Unmatched analog keys fall through to normalizeDpadAxis, which returns const [] for anything that is not a hat axis, so those events were discarded. On a DJI RC Pro the right stick produced no normalized events at all.

Both are mapped to rightStickX/rightStickY, the same aliasing pattern already used for AXIS_BRAKE/AXIS_GAS.

Guarding the cross-package invariant

AndroidMapping's correctness depends on the invert = true flags staying in the separately versioned Kotlin plugin, and until now the only trace of that was a comment on the Dart side. EventListener.kt is the more obvious place for a contributor to "fix" against Android's documentation, and doing so would silently re-invert everything without a single test failing, since the tests only exercise the Dart half. Added a counterpart comment next to supportedAxes pointing back at the Dart mapping.

AXIS_WHEEL is still reported by EventListener and still unmapped, since there is no matching GamepadAxis. It stays available through the raw event API.

Changes

• packages/gamepads/lib/src/mappings/android_mapping.dart
• packages/gamepads/lib/src/mappings/platform_mapping.dart, the Y-axis contract no longer lists Android as a platform that must negate
• packages/gamepads_android/.../EventListener.kt, comment only
• packages/gamepads/test/mappings_test.dart, stick assertions corrected, new RX/RY test
• packages/gamepads/test/gamepad_normalizer_test.dart, the AXIS_Y test asserted the buggy -1.0

Verification

melos analyze is clean, dart format reports no changes, and all 80 tests in packages/gamepads pass. Hardware confirmation on a physical Android device is still worth doing before release.

https://claude.ai/code/session_019aEP4Np5vqDw5BkgGYyHe7