Title: [Feature Request] Improve XCUITest Screen Recording

[tgz0514]

Two enhancement requests for XCUITest screen recording:

1. Save recording files directly on test device

• Allow custom path and format (e.g. $HOME/video.mp4 or $HOME/video.mov)

Current problems:

• Base64-encoded output is memory-intensive and inconvenient
• HTTP/HTTPS/FTP requires additional server setup and lacks clear documentation examples

2. Fix frame dropping on macOS

• Current startNativeScreenRecording has noticeable frame drops
• Native tools like QuickTime Player and screencapture don't have this issue
• Would appreciate insights into the technical differences and potential solutions

Environment:

• macOS 15.3
• Xcode 16.2

[mykola-mokhnach]

Save recording files directly on test device

I have added a possibility to retrieve the recorded payload as a stream using BiDi web socket. See #333 for more details.

In order to make it work it is necessary:

1. Enable BiDi by setting the webSocketUrl capability to true
2. Before starting a new video recording via macos: startNativeScreenRecording subscribe to the appium:mac2.nativeVideoRecordingChunkAdded BiDi event. Check https://github.com/appium/java-client/blob/15229beab2e4738612606d34ab26a306d85b1e1e/src/e2eIosTest/java/io/appium/java_client/ios/IOSBiDiTest.java#L32 for an example client implementation
3. Record each retrieved video chunk into a local file by decoding its payload from base64 and writing into a local file in the same sequence they arrive.
4. Call macos: stopNativeScreenRecording with ignorePayload set to true in order to finish the video recording. Close the resulting video file after this API returns.

Fix frame dropping on macOS

I don't think there is any reliable solution to it as the recording itself is done by the system daemon called testmanagerd. Maybe, try to bump its process CPU priority