Windows: harden BLE connection and GATT lifetimes

[usmanmehmood55]

Summary

This PR hardens the Windows BLE implementation around asynchronous connection, GATT-operation, subscription, and shutdown lifecycles.

Changes

• Retain GATT objects while reads, writes, descriptor operations, and discovery are in flight.
• Track connection attempts and queued connection events by generation so stale callbacks, failures, and disconnect events cannot affect newer connections.
• Validate existing native connections atomically before reusing or replacing them.
• Collapse duplicate in-progress connection attempts.
• Handle GattServicesChanged by refreshing the GATT map safely and restoring notification handlers for existing subscriptions.
• Register notification handlers before enabling the CCC descriptor, preventing an immediately emitted first notification from being lost.
• Make notification subscription changes transactional, including rollback after a failed CCC write and protection against overlapping operations.
• Improve descriptor read/write error handling during disconnects.
• Prevent new native callbacks from entering during plugin shutdown and drain callbacks already in progress before releasing plugin state.
• Dispatch COM apartment continuations and Windows messages while draining callbacks to avoid blocking UI-thread continuations during shutdown.
• Coalesce queued UI-thread wake-ups and discard queued work during shutdown.
• Make the Windows logger’s active level atomic.
• Normalize characteristic byte buffers at the Dart boundary so consumers do not receive unrelated platform-message bytes through value.buffer.
• Return descriptor values from BleCharacteristic.readDescriptor().

Validation

All current HIL tests were run:

• Baseline suite: 25 passed
• Fault-injection suite: 39 passed

Also manually verified:

• scanning
• connection/disconnection
• services/characteristics discovery
• data send/receive
• cleanup

[Copilot]

Pull request overview

Hardens Windows BLE asynchronous lifecycles and improves Dart-side value handling.

Changes:

• Adds connection generations, operation leases, shutdown tracking, and GATT refresh handling.
• Strengthens notification subscription and descriptor-operation behavior.
• Normalizes characteristic buffers and returns descriptor values from convenience APIs.

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
windows/test/CMakeLists.txt	Configures the tracker test.
windows/test/async_operation_tracker_test.cpp	Tests lease and shutdown behavior.
windows/src/universal_ble_plugin.h	Adds lifecycle and GATT state management.
windows/src/universal_ble_plugin.cpp	Implements Windows BLE hardening.
windows/src/ui_thread_handler.hpp	Coalesces and shuts down UI work.
windows/src/helper/universal_ble_logger.h	Makes logger state atomic.
windows/src/helper/universal_ble_logger.cpp	Implements atomic level access.
windows/src/async_operation_tracker.h	Introduces asynchronous-operation leases.
windows/CMakeLists.txt	Includes the tracker header.
test/device_id_case_insensitivity_test.dart	Tests buffer normalization.
test/ble_characteristic_test.dart	Tests descriptor reads.
lib/src/interfaces/universal_ble_platform_interface.dart	Normalizes received byte buffers.
lib/src/extensions/ble_characteristic_extension.dart	Returns descriptor read values.
CHANGELOG.md	Documents Windows hardening.

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[fotiDim]

@usmanmehmood55 please check the CoPilot review comments when you get the chance. We plan to make a release within the week.

[usmanmehmood55]

@fotiDim I've applied the changes pointed out by Copilot, waiting to access a Windows machine to run the HIL tests again. I'll push the changes in 2 hours or so.

[usmanmehmood55]

PR comments addressed, with all hardware in loop and fault injection tests passing for Windows.