[BUG] signUpWithPassword crashes on resolve: returns a LinkedHashMap instead of a WritableMap

[esaugomez31]

Describe the bug

On Android, signUpWithPassword crashes the app when the promise resolves (right after the credential is saved). The native module builds its success response with mapOf(...), which is a java.util.LinkedHashMap. The promise-resolve converter Arguments.fromJavaArgs only accepts WritableNativeMap/WritableNativeArray and primitives, so promise.resolve(...) throws. The credential save itself succeeds — only returning the result crashes. The sibling methods (signIn, createPasskey) already build their response with Arguments.createMap(), so only signUpWithPassword is affected.

Environment

• React Native version: 0.85.3 (New Architecture enabled)
• Library version: 0.8.1 (same mapOf is on main)
• Platform: Android
• Device information:
  • iOS: N/A
  • Android: any device, the failing step is a JS-bridge type conversion, not device-, OS-, or Kotlin-version-specific

Steps to Reproduce

1. On Android, call signUpWithPassword({ username, password }).
2. Accept the system password-manager save dialog.
3. The app crashes as the promise resolves.

Expected behavior

The promise resolves with the result and the app continues.

Actual behavior

The app crashes with:

java.lang.RuntimeException: Cannot convert argument of type class java.util.LinkedHashMap
    at com.facebook.react.bridge.Arguments.fromJavaArgs(Arguments.kt:159)
    at com.facebook.react.bridge.PromiseImpl.resolve(PromiseImpl.kt:29)
    at com.credentialsmanager.CredentialsManagerModule$signUpWithPassword$1.invokeSuspend(CredentialsManagerModule.kt:76)

Screenshots

N/A

Code snippet

await signUpWithPassword({ username: "user@example.com", password: "secret" })
// save succeeds, then the promise resolve crashes the app

The cause is in signUpWithPassword (both newarch and oldarch modules):

val result = mapOf("type" to "password", "username" to username, "success" to true)
promise.resolve(result) // LinkedHashMap is not a WritableNativeMap

Suggested fix — build a WritableMap, as signIn/createPasskey already do:

val result = Arguments.createMap().apply {
  putString("type", "password")
  putString("username", username)
  putBoolean("success", true)
}
promise.resolve(result)

Additional context

• Physical device and emulator: the crash is in the JS bridge type conversion, so it is independent of device/emulator.
• Latest version: yes, reproduced on 0.8.1 (latest published); the same mapOf is on main.
• Arguments.fromJavaArgs matches arguments against an exact-class whitelist (null, Boolean, Int, Double, Float, String, WritableNativeMap, WritableNativeArray), throwing on anything else, so a raw LinkedHashMap always fails.