fix(runtime): add Object.hasOwn polyfill for JSC compatibility

[bheemreddy-samsara]

Description

Adds Object.hasOwn polyfill to the runtime package for JSC (JavaScriptCore) compatibility.

JSC doesn't support Object.hasOwn (ES2022). This causes runtime errors when @vitest/expect v4.x initializes:

Object.hasOwn is not a function. (In 'Object.hasOwn(globalThis, MATCHERS_OBJECT)', 'Object.hasOwn' is undefined)

Related Issue

Fixes #52

Context

The error originates from @vitest/expect/dist/index.js:674:

if (!Object.hasOwn(globalThis, MATCHERS_OBJECT)) {

This was previously misattributed to Hermes (#51), but Hermes has supported Object.hasOwn in recent versions. The issue specifically affects JSC runtime, which is used when Hermes is disabled or on certain platform configurations.

Since react-native-harness targets React Native (which may use JSC) and depends on @vitest/expect v4.x, the polyfill belongs in the harness runtime rather than requiring every consumer to add it.

The polyfill is minimal and standards-compliant:

if (typeof Object.hasOwn !== 'function') {
  Object.hasOwn = (obj: object, prop: PropertyKey): boolean =>
    Object.prototype.hasOwnProperty.call(obj, prop);
}

Testing

• Tested on iOS simulator with JSC runtime
• Harness tests pass after adding this polyfill

References

• MDN: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/hasOwn

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