feat: add VFS audio resource loading and upgrade to Elementary v4

[txbrown]

Summary

• Add loadAudioResource/unloadAudioResource APIs for loading audio files into the Virtual File System
• Use miniaudio for cross-platform audio decoding (WAV, MP3, FLAC, Vorbis)
• Upgrade Elementary submodule and @elemaudio/core to v4.0.3
• Update JS Renderer for Elementary v4 API (sendMessage-only constructor)
• Fix audio buffer zeroing to prevent noise when no graph is active
• Add AudioBufferResource for proper multi-channel sample support

Closes #10

Test plan

• Build iOS example app
• Load audio samples via loadAudioResource()
• Play samples with el.sample({ path: key })
• Verify stereo samples play correctly (no double-trigger)
• Verify 440Hz tone still works
• Test Android build

[Copilot]

Pull request overview

This PR adds Virtual File System (VFS) audio resource loading capabilities and upgrades Elementary Audio to v4, enabling dynamic loading and playback of audio samples.

Changes:

• Added loadAudioResource/unloadAudioResource APIs with miniaudio-based cross-platform audio decoding
• Upgraded Elementary submodule and @elemaudio/core dependency from v2 to v4.0.3
• Updated NativeRenderer constructor to match Elementary v4's sendMessage-only API

Reviewed changes

Copilot reviewed 19 out of 29 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/index.tsx	Exported new VFS APIs and updated NativeRenderer for Elementary v4
src/NativeElementary.ts	Added TurboModule interface methods for audio resource management
package.json	Updated @elemaudio/core to v4.0.3
ios/Elementary.mm	Implemented audio resource loading/unloading with AudioBufferResource
ios/Elementary.h	Added loadedResources property for tracking loaded audio
ios/AudioResourceLoader.mm	iOS implementation of audio file decoding using miniaudio
cpp/AudioResourceLoader.h	Cross-platform audio loader header with metadata structures
cpp/AudioResourceLoader.cpp	C++ implementation of audio decoding and deinterleaving
cpp/audioengine.h	Added VFS method declarations and resource tracking
cpp/audioengine.cpp	Implemented audio resource management in AudioEngine
android/src/main/java/com/elementary/ElementaryModule.kt	Android native module implementation of VFS APIs
android/cpp-adapter.cpp	JNI bridge for audio resource operations
example/App.tsx	Comprehensive demo app showcasing sample loading and playback
AGENTS.md	Documentation for AI coding assistants

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[Copilot]

The constructor should document the breaking change from Elementary v2 (which required sampleRate) to v4 (which doesn't). Consider adding a JSDoc comment explaining this API change.

Suggested change

	export class NativeRenderer extends Renderer {
	export class NativeRenderer extends Renderer {
	/**
	* Create a NativeRenderer instance.
	*
	* Note: In Elementary v2, the Renderer constructor required a `sampleRate`
	* argument (e.g. `new Renderer(sampleRate, callback)`). In Elementary v4,
	* `sampleRate` is no longer passed to the constructor and is instead
	* determined internally by the native audio engine. This constructor follows
	* the v4 API and therefore does not accept or forward a `sampleRate`.
	*/

[Copilot]

The member initialization order in the constructor differs from the declaration order in the class (scratchData is declared before runtime). While this change corrects the initialization order to match declaration order, the magic number 2 for channel count should be documented or extracted as a named constant.