fix(android): resolve signUpWithPassword with a WritableMap

[qamarq]

Fixes #23.

Problem

On Android, signUpWithPassword saves the credential and then crashes the app when it resolves the promise:

java.lang.RuntimeException: Cannot convert argument of type class java.util.LinkedHashMap
  at com.facebook.react.bridge.Arguments.fromJavaArgs
  at com.facebook.react.bridge.PromiseImpl.resolve
  at com.credentialsmanager.CredentialsManagerModule$signUpWithPassword$1.invokeSuspend

The success result is built with Kotlin mapOf(...), which is a java.util.LinkedHashMap. Promise.resolve only accepts primitives and WritableMap/WritableArray, so it throws. The exception is raised inside the coroutine, so it takes down the process and can't be caught from JS. The other methods (signIn, createPasskey) already build their results with Arguments.createMap(), so only signUpWithPassword is affected.

Change

Build the result with Arguments.createMap() in both the new and old architecture modules. The shape resolved to JS is unchanged: { type: "password", username, success: true }.

We've been running this as a pnpm patch on 0.8.1 in production (Expo SDK 57, React Native 0.86, New Architecture). Saving a password after sign-up and after email login no longer crashes.

[qamarq]

@benjamineruvieru ^

[benjamineruvieru]

@benjamineruvieru ^

Thank you for your contribution