[Repo Assist] fix: async { for x in taskSeq } no longer wraps exceptions in AggregateException

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Closes #129

Root cause

AsyncExtensions.fs used Async.AwaitTask to await the task returned by TaskSeq.iterAsync. Async.AwaitTask always wraps task exceptions in AggregateException, meaning that try/catch blocks in async {} expressions that iterate over a taskSeq with for could not catch the original exception type:

// Before this fix: catch block receives AggregateException, not InvalidOperationException
async {
    for item in myTaskSeq do
        try
            doSomethingThatMightThrow item
        with :? InvalidOperationException -> // <-- this did NOT match
            ()
}

Fix

Replace Async.AwaitTask with a private awaitTaskCorrect function using Async.FromContinuations that:

• Unwraps single inner exceptions from AggregateException before routing to the error continuation
• Propagates multi-exception AggregateException as-is (correct for cases with multiple concurrent failures)
• Correctly routes task cancellation to the async cancellation continuation

This is the standard AwaitTaskCorrect pattern discussed extensively in the F# community (see fslang-suggestions#840).

Files changed

• src/FSharp.Control.TaskSeq/AsyncExtensions.fs — add awaitTaskCorrect, replace Async.AwaitTask
• src/FSharp.Control.TaskSeq.Test/TaskSeq.AsyncExtensions.Tests.fs — 2 new regression tests
• release-notes.txt — entry under v0.6.0

AI Disclosure

This PR was created by Repo Assist, an automated AI assistant.

Test Status

✅ Build: succeeded (Release configuration, netstandard2.1)
✅ Tests: 4530 passed, 2 skipped, 0 failed — full suite
✅ New tests: 2 regression tests in ExceptionPropagation module (50 total in AsyncExtensions)
✅ Formatting: dotnet fantomas . --check passes

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