Step 4: `ReliaBLEManager` → nonisolated `Sendable` final class + rename `BluetoothManager` → `BluetoothActor`

[itsniper]

Goal

Make ReliaBLEManager a nonisolated Sendable final class that forwards async calls to BluetoothActor. Collapse the now-internal BluetoothManager into the actor type (renaming BluetoothManager → BluetoothActor). Delete dead code.

Context

See the investigation report at docs/investigations/swift6-concurrency-audit-2026-05-13.md, sections Investigator Findings §4, Recommendations §A ("Why nonisolated ReliaBLEManager and not @MainActor"), and Risks §7 (naming).

This step finishes the architectural goal: the library is callable cleanly from @MainActor SwiftUI and from background actors, without forcing a MainActor hop on background callers. A @MainActor façade would have forced that hop; a nonisolated Sendable façade does not.

Deliverable (Step 4 of 5 in the migration plan)

1. Mark public final class ReliaBLEManager: Sendable. All members become forwarders.
2. Public actions become async (authorizeBluetooth, startScanning, stopScanning, future connect/disconnect).
3. currentState becomes get async.
4. Rename BluetoothManager → BluetoothActor. Move the file's responsibilities entirely inside the actor; remove the legacy NSObject shape. Keep BluetoothManager.swift as the filename (it now declares the actor) so DocC anchor history stays sane, or rename to BluetoothActor.swift if anchor breakage is acceptable — call this out in the PR for review.
5. Collapse / inline PeripheralManager into the actor (its queue.sync pattern becomes plain actor isolation). The standalone PeripheralManager type goes away.
6. Delete dead code:
   • testFunction() in ReliaBLEManager.swift:106
   • AuthorizationError.unauthorized if it's still unused after the refactor (the only case currently is denied/restricted/unknown)
7. Preserve forceMock: true literal at the factory call site (load-bearing per CLAUDE.md).
8. Update the Demo's CentralViewModel to call await manager.… everywhere; wrap actions in Task { … } from @MainActor view methods.

Acceptance criteria

• ReliaBLEManager: Sendable. A unit test captures a ReliaBLEManager reference into a Task.detached and calls every public method — must compile.
• BluetoothActor is the global actor. BluetoothManager symbol no longer exists.
• PeripheralManager symbol no longer exists (inlined into the actor).
• All public methods that mutate / read state are async.
• forceMock: true literal remains at the factory call site.
• DocC catalog updated (architecture page reflects the renames; ReliaBLEManager → BluetoothActor link from the manager page).

Not in scope

• Logging polish + strict-concurrency flag flip is Step 5.
• Removing the Combine surface happened in Step 3 (Remove Combine #12); this step can assume AsyncStream is already in place.

References

• Investigation report: docs/investigations/swift6-concurrency-audit-2026-05-13.md
• Parent: Update for Swift Concurrency in Swift 6 #10
• Depends on: Make BluetoothManager Swift 6 safe #13 (Step 1), Step 2 issue, Remove Combine #12 (Step 3)