feat: nitro modules 37 upgrade

[RainbowPlayer]

Upgrades the native integration from Nitro Modules 0.35 to 0.37.1. The JavaScript date API is unchanged.

Changes

• nitrogen and react-native-nitro-modules (dev + both examples): 0.35.7 → 0.37.1
• Peer dependency: >=0.35.0 <0.36.0 → >=0.37.0 <0.38.0
• Package version 3.0.0 → 4.0.0 (major, because the native peer range changed)
• README, docs, CHANGELOG and RELEASE_NOTES_v4.0.0.md updated

Validation

• Nitrogen 0.37.1 generates byte-identical code for the current spec compared to Nitrogen 0.35.7 (all 17 generated files).
• Nitro 0.36/0.37 changes target the Nitro View pipeline (props, component descriptors, recycling) and Kotlin/JNI internals; NativeDate is a plain C++ HybridObject, so no source changes are needed.
• bob build (including the nitrogen step), tsc and the full Jest suite pass (923/923 with TZ=UTC).

Note: 4 tests in standards.test.ts fail when run in a non-UTC local timezone (e.g. Europe/Kyiv). They fail the same way on main, so they are unrelated to this change.

Supersedes #7 (Nitro 0.36), since the generated code is identical across 0.35 → 0.37.