refactor: add Obsolete attributes to outdated methods

[vbreuss]

This PR prepares Testably.Abstractions.Testing for the upcoming v6.0.0 release by marking selected legacy APIs as obsolete so consumers can migrate before removal.

Key Changes:

• Made Notification.ExecuteWhileWaiting(...) and related helper types unconditionally [Obsolete].
• Made IAwaitableCallback<TValue>.Wait(filter, ...) unconditionally [Obsolete].
• Made MockTimeSystem(ITimeProvider) unconditionally [Obsolete].

[Copilot]

Pull request overview

This PR prepares Testably.Abstractions.Testing for the upcoming v6.0.0 release by marking selected legacy APIs as obsolete so consumers can migrate before removal.

Changes:

• Made Notification.ExecuteWhileWaiting(...) and related helper types unconditionally [Obsolete].
• Made IAwaitableCallback<TValue>.Wait(filter, ...) unconditionally [Obsolete].
• Made MockTimeSystem(ITimeProvider) unconditionally [Obsolete].
• Updated the net10.0 API approval baseline to reflect the new attributes.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
Tests/Api/Testably.Abstractions.Api.Tests/Expected/Testably.Abstractions.Testing_net10.0.txt	Updates API approval baseline (net10.0) to include new [Obsolete] attributes.
Source/Testably.Abstractions.Testing/Notification.cs	Removes conditional compilation and always applies [Obsolete] to ExecuteWhileWaiting APIs and related types.
Source/Testably.Abstractions.Testing/MockTimeSystem.cs	Removes conditional compilation and always applies [Obsolete] to the ITimeProvider constructor.
Source/Testably.Abstractions.Testing/IAwaitableCallback.cs	Removes conditional compilation and always applies [Obsolete] to the Wait(filter, ...) overload.

Comments suppressed due to low confidence (1)

Source/Testably.Abstractions.Testing/IAwaitableCallback.cs:39

• This Wait(filter, timeout, ...) overload is now unconditionally [Obsolete]. There are existing tests that call it (e.g., wait.Wait(t => ...)) and they currently guard their own [Obsolete] annotations behind MarkExecuteWhileWaitingNotificationObsolete, which doesn’t appear to be defined. Please either update those tests to use the non-obsolete Wait/WaitAsync overloads (and apply the filter at callback creation time) or suppress CS0618 in the specific tests that intentionally cover the obsolete overload.

	[Obsolete("Use another `Wait` or `WaitAsync` overload and move the filter to the creation of the awaitable callback.")]
	void Wait(Func<TValue, bool>? filter = null,
		int timeout = 30000,
		int count = 1,
		Action? executeWhenWaiting = null);

[github-actions]

Test Results

    102 files  ± 0      102 suites  ±0   2h 27m 38s ⏱️ + 2m 1s
112 452 tests  - 17   99 849 ✅  - 17  12 603 💤 ±0  0 ❌ ±0 
267 982 runs  ± 0  231 454 ✅ ± 0  36 528 💤 ±0  0 ❌ ±0 

Results for commit c8fad59. ± Comparison against base commit 1666aa9.

♻️ This comment has been updated with latest results.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

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

See analysis details on SonarQube Cloud