Support wasm target

[Him188]

Summary

Adds wasm/browser support for MediaMP by wiring wasmJs targets into the public modules and introducing a browser-backed WebMediampPlayer implementation based on HTMLVideoElement.

This also adds a Compose wasm preview app so consumers can try playback directly in the browser.

Changes

• Add wasmJs { browser() } targets for mediamp-api, mediamp-source-ktxio, mediamp-test, and mediamp-all.
• Add wasm actuals for player factory loading and MediampPlayerSurface.
• Add WebMediampPlayer with URI playback, seek, play/pause/stop/close, progress and media properties, subtitles, volume/mute, playback speed, aspect-ratio controls, and media metadata.
• Add wasm tests for factory creation, media source setup, subtitle track installation, feature controls, and stop/close behavior.
• Add mediamp-web-preview for browser validation and manual preview.
• Keep the existing public UI-thread annotation surface as androidx.annotation.UiThread; no new MediaMP-owned public UiThread annotation is introduced.

User impact

Consumers targeting Compose Web / wasm can now depend on MediaMP and render a player surface in browser apps. Playback uses browser-native media support, so codec support, CORS, Range requests, and autoplay behavior follow the browser's HTMLVideoElement rules.

Validation

• ./gradlew :mediamp-api:wasmJsTest :mediamp-test:wasmJsTest :mediamp-source-ktxio:compileKotlinWasmJs :mediamp-all:compileKotlinWasmJs :mediamp-web-preview:wasmJsBrowserDevelopmentWebpack --no-daemon --console=plain -Pkotlin.daemon.jvmargs=-Xmx8g
• ./gradlew :mediamp-web-preview:compileKotlinWasmJs --no-daemon --console=plain
• Browser validation with Chrome against http://localhost:8080/: located the shadow-DOM <video>, confirmed default MP4 playback, readyState=4, currentTime advanced from 0 to about 2.46s, video size was 960x540, and one subtitle track was installed.