fix: TypeScript ESLint unbound-method errors in Auth0 context interface

[subhankarmaiti]

Fixes #1334

This PR resolves TypeScript ESLint unbound-method errors that occurred when using strict type-checking configurations with the react-native-auth0 SDK. The issue was reported when users enabled the recommended-type-checked preset from @typescript-eslint, which flagged destructured methods from the useAuth0() hook.

Changes

1. src/hooks/Auth0Context.ts

   • Converted all 21 method signatures in Auth0ContextInterface from method syntax (methodName(): Type) to arrow function property syntax (methodName: () => Type)
   • This change signals to TypeScript and ESLint that these methods don't depend on this context and are safe to destructure

2. src/platforms/native/bridge/NativeBridgeManager.ts

   • Updated all 13 native module method calls to use .bind(Auth0NativeModule) when passing to the a0_call wrapper
   • Ensures proper this context preservation when calling native methods

3. eslint.config.mjs

   • Added TypeScript-specific configuration block enabling the @typescript-eslint/unbound-method rule
   • Added typescript-eslint package for unified configuration
   • Configured type-checked linting for TS/TSX files (excluding test files)
   • This ensures future code changes maintain the correct interface typing pattern

4. package.json

   • Added typescript-eslint as a dev dependency for ESLint configuration

Testing

• ✅ All TypeScript compilation passes
• ✅ Verified 0 unbound-method errors with recommended-type-checked config
• ✅ Tested destructuring patterns in example app
• ✅ Root project linting passes with no new errors

Breaking Changes

None. This is a backward-compatible change that only affects type definitions to improve compatibility with strict TypeScript ESLint configurations.

Developer Experience Impact

✅ Positive Impact: Developers using strict TypeScript ESLint configurations (like recommended-type-checked) can now use the SDK without linting errors when destructuring methods from the useAuth0() hook.

// This pattern now works without ESLint errors:
const { authorize, getCredentials, clearSession } = useAuth0();