Fix/release build expo

[HuuNguyen312]

Summary

Fixes #406.

On Android, react-native-compressor (Nitro) works in debug but fails to link in release builds — NitroModules.createHybridObject('Compressor') throws the linking error, so the module is unusable in production (reported on RN 0.85.3
/ Expo).

Why this happens — R8 strips a JNI-instantiated class:

The Compressor HybridObject implementation is created from C++/JNI by class-name string (generated NitroCompressorOnLoad.cpp):

static constexpr auto kJavaDescriptor = "Lcom/margelo/nitro/compressor/HybridCompressor;";
... javaClassStatic()->newObject(constructorFn);   // JNI instantiation of the impl class

R8 can't see that reference (it's a string in native code). The generated HybridCompressorSpec carries @DoNotStrip @Keep and survives, but the hand-written implementation HybridCompressor had no keep protection — so a consumer's release R8
removes/renames it. The JNI findClass/newObject then fails and the HybridObject is never registered. Debug works because R8 doesn't run.

This is the same reason other Nitro modules (e.g. react-native-mmkv) annotate their implementation class — nitrogen and the Nitro convention expect @DoNotStrip @Keep on the impl. This module was simply missing it.

The fix: Annotate HybridCompressor with @DoNotStrip @Keep (matching the generated spec and the convention used by other Nitro modules). No consumer ProGuard rules are needed.

Changelog

[ANDROID] [FIXED] - Keep the HybridCompressor Nitro implementation from R8 stripping so the Compressor HybridObject links in release builds (#406)

Test Plan

- [x] Ran local JS PR gate: yarn test:pr (unaffected — native-only change)
- [x] Reproduced and verified the fix with a real minified release build (enableProguardInReleaseBuilds = true, :app:assembleRelease, R8 enabled), inspecting R8's own output:

- Without the annotation — class is stripped:
# usage.txt (R8 removed list)
com.margelo.nitro.compressor.HybridCompressor

- With @DoNotStrip @Keep — class + no-arg constructor kept, not renamed:
# mapping.txt
com.margelo.nitro.compressor.HybridCompressor -> com.margelo.nitro.compressor.HybridCompressor:
    ... void <init>() -> <init>
- [x] Confirmed the same convention in react-native-mmkv (HybridMMKVPlatformContext is annotated @DoNotStrip @Keep).

▎ Note: verified via the bare example's minified release build (R8 mapping/usage output). I did not run the user's exact Expo expo run:android --variant release, but R8 behavior on the consuming app is what the annotation protects against.