[lijy91]

Expose CaptureSource, ScreenCapturer and ScreenRecorder across Dart, Rust, C#, JavaScript, Python and Go, with generated API reference and a Flutter desktop example for source selection, cropped screenshots, PNG saving and silent MP4 recording. Fix screenshot previews to decode the data URI returned by Image.toBase64().

Depends on libnativeapi/nativeapi-core#86. The core gitlink points to published commit ecdf94e9dbd8ddc8f74f43ae7e31154c96da2795. Merge core first; refresh this gitlink if core is squash-merged.

Generator changes support static utility classes, nested value ownership and Rust trait/import requirements. Preserve the C# clipboard formatting already present on main in the generator itself. Update native linking, binding regression tests, the Dart changelog and specs/screen-capture.md.

Validation:

• ./codegen sync completed, including Rust bindgen and Dart ffigen.
• ./codegen check passes: 81 C ABI files and 366 binding/reference files; no new skipped APIs.
• Code generator tests and Flutter example analysis pass.
• Latest-base macOS core build and screen_capture_test pass.
• Earlier implementation checks covered Rust/Dart/C#/JS/Python/Go builds or analysis, with Rust/JS/Python/Go ABI tests; native desktop smoke tests passed on macOS and Windows.
• The macOS Flutter example was run with a successful 2560 × 1440 screenshot and short MP4 recordings. The Windows Flutter example has not yet been run.

Draft / remaining work:

• Complete the acceptance checklist in specs/screen-capture.md: permission denial, source invalidation, long recordings and asynchronous runtime teardown.
• Generated options defaults are not consistent with C++; the example supplies fields explicitly.
• The example's Open folder / Open / Play actions currently fail because UrlOpener accepts HTTP/HTTPS only. Saved PNG/MP4 files can be opened manually using their displayed paths.
• No audio or pause/resume support. Other core platforms remain unsupported stubs.