feat: Migration from phone to phone

[tevincent]

No description provided.

[Copilot]

Pull request overview

This PR introduces device-to-device migration support by leveraging platform backups/transfers to restore account state, then re-initializing passkeys on the new device using a marker-folder mechanism to ensure the process runs once per account.

Changes:

• Add multiplatform file utilities (expect/actual) to create/check a marker folder and per-account marker files.
• Add a “backed up accounts” handling path that re-authenticates with the restored passkey, registers a new passkey, persists a fresh token, and updates account status.
• Enable Android backup/device-transfer rules and turn android:allowBackup on, excluding only the marker folder.

Reviewed changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
multiplatform-lib/src/commonMain/kotlin/utils/FileUtils.kt	Declares common expect APIs for marker folder/file operations.
multiplatform-lib/src/androidMain/kotlin/utils/FileUtils.android.kt	Android implementations of marker folder/file operations in filesDir.
multiplatform-lib/src/appleMain/kotlin/utils/FileUtils.apple.kt	Apple implementations using Application Support directory (+ exclude from iCloud backup).
multiplatform-lib/src/appleMain/kotlin/internal/utils/FileUtils.kt	Adds helper to resolve Application Support directory on Apple platforms.
multiplatform-lib/src/commonMain/kotlin/internal/managers/MigrationManager.kt	Adds backed-up account re-initialization (re-register passkey + refresh token).
multiplatform-lib/src/commonMain/kotlin/internal/AuthenticatorFacadeImpl.kt	Calls backed-up account handler before legacy migration; writes marker files on addAccounts.
multiplatform-lib/src/commonMain/kotlin/internal/managers/AuthenticatorManager.kt	registerPasskey now returns keyId; token retrieval supports explicit keyId; adds keyId getter.
multiplatform-lib/src/commonMain/kotlin/internal/KeyManager.kt	Updates KeyPairManager API to search by predicate.
multiplatform-lib/src/commonMain/kotlin/internal/KeyPairManagerImpl.kt	Updates expect declaration for new predicate-based lookup.
multiplatform-lib/src/androidMain/kotlin/internal/KeyPairManagerImpl.android.kt	Implements predicate-based keyId lookup; small refactor naming.
multiplatform-lib/src/appleMain/kotlin/internal/KeyPairManagerImpl.apple.kt	Implements predicate-based keyId lookup in Keychain scanning logic.
app/src/main/res/xml/data_extraction_rules.xml	Enables broad device-transfer inclusion of files+db, excludes marker folder.
app/src/main/res/xml/backup_rules.xml	Enables broad Auto Backup (API<31) inclusion of files+db, excludes marker folder.
app/src/main/AndroidManifest.xml	Enables android:allowBackup="true" and hooks up the above rule files.

Comments suppressed due to low confidence (1)

multiplatform-lib/src/commonMain/kotlin/internal/managers/AuthenticatorManager.kt:120

• The delete predicate "-$passkeyId-" in it won’t match iOS Keychain tags generated as "$userId-$keyId" (no trailing -). As a result, passkeys may never be deleted on iOS. Align the predicate with the platform storage naming/tagging scheme (e.g., exact match or startsWith("$userId-$passkeyId")).

    suspend fun removeAccount(token: String, userId: Long) {
        val passkeyId = keyPairManager.findKeyIdFor { it.startsWith("$userId-") }.firstOrNull()

        if (passkeyId != null) {
            // If we have a passkey for this account, revoke it against the backend and delete it
            webAuthnRepository.deletePasskey(token, passkeyId)
            val _ = keyPairManager.deleteKeysMatching { "-$passkeyId-" in it }
        }

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
20 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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