feat(ios): add CoreBluetooth state restoration

[delmoncompanysa-eng]

Opt the central manager into state preservation/restoration via CBCentralManagerOptionRestoreIdentifierKey and implement centralManager(_:willRestoreState:) so iOS can relaunch the app in the background when a managed peripheral reconnects and hand the live connection back. The manager is eagerly created at plugin registration (inside didFinishLaunchingWithOptions) so willRestoreState can fire.

[gemini-code-assist]

Code Review

This pull request implements CoreBluetooth state preservation and restoration for iOS in the UniversalBlePlugin Swift code. It eagerly instantiates the central manager during plugin registration and configures it with a stable restoration identifier. It also implements the centralManager(_:willRestoreState:) delegate method to re-adopt restored peripherals. Feedback on these changes suggests removing the insertion of restored peripherals into autoConnectDevices because it may override the original auto-connect configuration, and notes that autoConnectDevices is currently an unused variable that should be cleaned up entirely.

[delmoncompanysa-eng]

Thanks — good catch. Fixed in 81badf3: removed the unconditional autoConnectDevices.insert(...) in willRestoreState, since CoreBluetooth restores peripherals regardless of their autoConnect configuration and the set isn't read for reconnection. Auto-connect intent now stays solely what connect(autoConnect:) recorded. Fully removing the (pre-existing) unused autoConnectDevices set is outside this PR's scope, but happy to do it in a follow-up if you'd prefer.

[Copilot]

Pull request overview

Adds iOS CoreBluetooth state preservation/restoration support to the Darwin implementation so iOS can relaunch the app in the background and hand back restored CBPeripheral connections, by ensuring the CBCentralManager is created with a restoration identifier early during app launch.

Changes:

• Opts the iOS CBCentralManager into state restoration via CBCentralManagerOptionRestoreIdentifierKey, and forces eager manager creation at plugin registration time.
• Implements centralManager(_:willRestoreState:) to re-adopt restored peripherals (delegate + cache repopulation) and best-effort notify Dart if already connected.
• Updates the example lockfile to reflect the plugin version bump and Dart SDK resolution floor.

Reviewed changes

Copilot reviewed 1 out of 2 changed files in this pull request and generated no comments.

File	Description
example/pubspec.lock	Updates resolved plugin version and SDK resolution metadata for the example app.
darwin/universal_ble/Sources/universal_ble/UniversalBlePlugin.swift	Adds iOS state restoration identifier/configuration, eager manager init on registration, and restoration callback handling to rehydrate peripherals.

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[fotiDim]

@delmoncompanysa-eng thanks for the PR. Overall looks good although it is a bit heavy on comments. Could you please slim them down and keep them only where necessary? I could also do it after merge.

[fotiDim]

@delmoncompanysa-eng we should also update the readme and document the new behavior. Is there a plist entry required?

[delmoncompanysa-eng]

Done — slimmed the state-restoration comments to keep only the "why", documented the new iOS background state restoration behavior in the README (Permissions → iOS / macOS), and added a CHANGELOG entry.

Regarding the plist: yes. The consuming app must declare the bluetooth-central background mode under UIBackgroundModes in its Info.plist; without it iOS won't relaunch the app for Bluetooth events and willRestoreState: won't fire. I've documented this in the README.