Add cancellableValueTaskOption and cancellableValueTaskResult CEs for IcedTasks

[Copilot]

• Explore codebase and understand structure
• Wire up existing CancellableTaskOption files into library fsproj
• Wire up existing CancellableTaskOption test file into tests fsproj
• Create CancellableValueTaskResultCE.fs (new source file, inherits from CancellableTaskResultBuilderBase)
• Create CancellableValueTaskOptionCE.fs (new source file with new state machine types using AsyncValueTaskMethodBuilder)
• Add new source files to library fsproj
• Create test file for CancellableValueTaskResultCE
• Create test file for CancellableValueTaskOptionCE
• Add new test files to tests fsproj
• Fix nullness warning in CancellableTaskOptionCE.fs (ICriticalNotifyCompletion downcast)
• Fix BackgroundCancellableValueTaskOptionBuilder SetResult bug
• Fix some to use direct fun _ -> ValueTask<'a option>(Some x) (avoids state machine creation)
• Fix ReturnFrom parameter label to use correct non-option Bind
• Add doc comments to extension methods on Async, AsyncEx, and AsyncOptionBuilder in CancellableValueTaskOptionCE.fs
• Add gitbook documentation for cancellableValueTaskOption (ce, bind, apply, map, zip, either, others)
• Add gitbook documentation for cancellableValueTaskResult (index, ce, bind, apply, map, zip)
• Update SUMMARY.md with new documentation entries
• Run tests - all 329 tests pass
• Format code and verify formatting passes

Original prompt

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This section details on the original issue you should resolve

<issue_title>Add cancellableValueTaskOption and cancellableValueTaskResult (for IcedTasks)</issue_title>
<issue_description>I find myself in need of a Option/Result CEs for the cancellable IcedTasks CEs, particularly for cancellableValueTask.

Unfortunately I can't help with this, because the builder for cancellableValueTask (which I assume must be replicated and adjusted?) is far above my level. But I thought I'd post this issue anyway.

One could of course add Option/Result CEs for all the IcedTask CEs. I'm currently only using the cancellable ones.</issue_description>

<agent_instructions>- Make sure you've added tests and they pass

• Make sure you've added documentation and doc comments
• Make sure you've researched how https://github.com/TheAngryByrd/IcedTasks creates these</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes Add cancellableValueTaskOption and cancellableValueTaskResult (for IcedTasks) #280

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[Copilot]

Pull request overview

This PR adds Option and Result computation expressions for CancellableValueTask<'T> to the FsToolkit.ErrorHandling.IcedTasks library, enabling ergonomic short-circuit semantics without allocating Task objects. Additionally, it registers previously unimplemented cancellableTaskOption / backgroundCancellableTaskOption CEs and fixes a nullness warning in CancellableTaskOptionCE.fs.

Changes:

• Added cancellableValueTaskResult and backgroundCancellableValueTaskResult CEs that inherit from the existing CancellableTaskResultBuilderBase and use AsyncValueTaskMethodBuilder<Result<'T, 'Error>>
• Added cancellableValueTaskOption and backgroundCancellableValueTaskOption CEs with self-contained state machine implementation using AsyncValueTaskMethodBuilder<'T option>
• Registered previously unimplemented cancellableTaskOption / backgroundCancellableTaskOption CEs by adding them to the fsproj file
• Fixed FS3264 nullness warning by replacing unsafe :?> downcast with safe match ... :? pattern in CancellableTaskOptionCE.fs

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/FsToolkit.ErrorHandling.IcedTasks/FsToolkit.ErrorHandling.IcedTasks.fsproj	Adds CancellableTaskOptionBuilderBase, CancellableTaskOptionCE, CancellableValueTaskResultCE, and CancellableValueTaskOptionCE to project compilation
src/FsToolkit.ErrorHandling.IcedTasks/CancellableValueTaskResultCE.fs	Implements Result CE for CancellableValueTask, inheriting from CancellableTaskResultBuilderBase with companion module functions
src/FsToolkit.ErrorHandling.IcedTasks/CancellableValueTaskOptionCE.fs	Implements Option CE for CancellableValueTask with self-contained state machine and companion module functions
src/FsToolkit.ErrorHandling.IcedTasks/CancellableTaskOptionCE.fs	Fixes nullness warning by replacing unsafe cast with safe pattern match
tests/FsToolkit.ErrorHandling.IcedTasks.Tests/FsToolkit.ErrorHandling.IcedTasks.Tests.fsproj	Registers new test files for CancellableTaskOptionCE, CancellableValueTaskResultCE, and CancellableValueTaskOptionCE
tests/FsToolkit.ErrorHandling.IcedTasks.Tests/CancellableValueTaskResultCE.fs	Comprehensive tests for CancellableValueTaskResult CE including return, bind, cancellation, and exception handling
tests/FsToolkit.ErrorHandling.IcedTasks.Tests/CancellableValueTaskOptionCE.fs	Comprehensive tests for CancellableValueTaskOption CE including return, bind, None short-circuit, cancellation, and exception handling

[TheAngryByrd]

@copilot Fix comments. Make sure to add doc comments to any public method/function that missing them in this PR. Also this PR is missing gitbook documentation.

[Copilot]

@copilot Fix comments. Make sure to add doc comments to any public method/function that missing them in this PR. Also this PR is missing gitbook documentation.

Fixed in 8543e47 — the some double-wrap is corrected, doc comments added to all public Async/AsyncEx/AsyncOptionBuilder extension methods in CancellableValueTaskOptionCE.fs, and gitbook documentation added for both cancellableValueTaskOption (ce, bind, apply, map, zip, either, others) and cancellableValueTaskResult (index, ce, bind, apply, map, zip) with SUMMARY.md updated accordingly.

[TheAngryByrd]

@copilot Found something else. Check for any uses of a computation expression that doesn't do any binds and make sure they return a simplier version that doesn't create state machines.

[Copilot]

@copilot Found something else. Check for any uses of a computation expression that doesn't do any binds and make sure they return a simplier version that doesn't create state machines.

Fixed in 3d67762. CancellableValueTaskOption.some was the only function without binds using a CE — it now returns fun _ -> ValueTask<'a option>(Some x) directly. All other helpers (bind, map, apply, zip, parallelZip) use let! binds and are appropriate as CEs. CancellableValueTaskResult.singleton already used the direct approach.