Verify device's preferred Thread dataset after import

[agners]

Summary

After a Thread sync with coreIsDevicePreferred == false && appIsDevicePreferred == true (i.e. the device prefers an app-added credential that doesn't match HA's preferred dataset), fullSyncPreferredDataset deletes mismatched border-agent IDs and re-imports HA's preferred TLV via ThreadNetworkClient.addCredentials. The path then unconditionally returned updated = true and the developer settings screen reported "Updated network from Home Assistant on this device".

ThreadNetworkClient.addCredentials only stores a credential under the supplied border agent — the Google Play Services Thread API does not expose any way to set the preferred dataset, and Play Services often keeps preferring the older app-added credential. As a result the device's preferred dataset was unchanged, the next sync re-detected the same mismatch, ran the same delete-and-import again, and reported success again. The user-visible outcome was an apparently successful sync that looped indefinitely without actually changing what Play Services preferred.

This PR makes the report honest:

• After importDatasetFromServer succeeds, isPreferredCredentials is queried for the just-imported TLV.
• The result is exposed via a new deviceNowPrefersCore: Boolean? field on SyncResult.AllHaveCredentials.
• The developer settings screen shows a dedicated message (thread_debug_result_updated_not_preferred) when the device still prefers a different network, with a non-success indicator, so the user knows that another sync won't resolve the state.

It also fixes a cosmetic log issue surfaced while debugging this: the "device prefers app added dataset" line was printing the extended PAN ID via String(ByteArray), which produces control characters. It now formats the EXTPAN as upper-case hex.

This is a companion to #6818, which addresses the symmetric problem on the server side (thread/add_dataset_tlv does not promote a dataset to preferred either). Both stem from the same underlying issue: neither the server-side WS command (since home-assistant/core#108278) nor the Play Services addCredentials call promote the just-added dataset, so the app must verify and report rather than assume.

A deeper follow-up is still needed on the device side: getThreadBorderAgentIds() is replaced (not appended) on every successful import, so border-agent IDs HA used in earlier sessions are no longer tracked and the cleanup loop won't remove them. Iterating ThreadNetworkClient.allCredentials and removing every owned credential whose BA doesn't match the current core preferred would address that, but it's a more invasive change and is intentionally not part of this PR.

Checklist

• New or updated tests have been added to cover the changes following the testing guidelines.
• The code follows the project's code style and best_practices.
• The changes have been thoroughly tested, and edge cases have been considered.
• Changes are backward compatible whenever feasible. Any breaking changes are documented in the changelog for users and/or in the code for developers depending on the relevance.

Screenshots

Link to pull request in documentation repositories

Any other notes

ThreadManager.SyncResult.AllHaveCredentials gains a new deviceNowPrefersCore constructor parameter. All in-tree callers are updated; the change is contained in the app module.

[Copilot]

Pull request overview

This PR improves the Thread credential “sync preferred dataset” flow by verifying whether Google Play Services actually switched the device’s preferred Thread dataset after importing Home Assistant Core’s preferred dataset, and reporting the outcome accurately in Developer Settings.

Changes:

• Add deviceNowPrefersCore: Boolean? to ThreadManager.SyncResult.AllHaveCredentials to surface post-import preferred-dataset verification.
• Update Developer Settings messaging to distinguish “updated” vs “updated but still not preferred” and mark the latter as non-success.
• Fix Thread debug logging to format the extended PAN ID as uppercase hex (instead of String(ByteArray) control characters).

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
common/src/main/res/values/strings.xml	Adds a new debug string for the “updated but still not preferred” state
app/src/main/kotlin/io/homeassistant/companion/android/thread/ThreadManager.kt	Extends AllHaveCredentials result with deviceNowPrefersCore
app/src/main/kotlin/io/homeassistant/companion/android/settings/developer/DeveloperSettingsPresenterImpl.kt	Uses deviceNowPrefersCore to choose message and success indicator
app/src/full/kotlin/io/homeassistant/companion/android/thread/ThreadManagerImpl.kt	Verifies preferred dataset after import; improves logging of EXTPAN