fix(powershell): run `atuin history end` in the background (#3034)

This runs `atuin history end` in the background, since it could delay
the next prompt when syncing.

Sorry I didn't realize this command could be slow (I currently don't use
sync).

I went for the .NET [`Process`
class](https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.process),
which is not pretty, but the other solutions I thought about all had
their own issues (`Start-Process` needs a file to redirect the output so
you can't just ignore it, `Start-Job` creates job objects that will
linger, `&` does the same but doesn't work on PS 5.1, ...). I'm
surprised I couldn't find a nice way to do the equivalent of `command &
>/dev/null` in PowerShell. 😕

This replaces #3033

## Checks
- [x] I am happy for maintainers to push small adjustments to this PR,
to speed up the review cycle
- [x] I have checked that there are no existing pull requests for the
same thing

1 files changed, 13 insertions, 2 deletions

diff --git a/crates/atuin/src/shell/atuin.ps1 b/crates/atuin/src/shell/atuin.ps1
index f1caee86..501c1145 100644
--- a/crates/atuin/src/shell/atuin.ps1
+++ b/crates/atuin/src/shell/atuin.ps1
@@ -51,9 +51,20 @@ New-Module -Name Atuin -ScriptBlock {
             $duration = (Get-History -Count 1).Duration.Ticks * 100
             $durationArg = if ($duration) { "--duration=$duration" } else { $null }
 
-            atuin history end --exit=$exitCode $durationArg -- $script:atuinHistoryId | Out-Null
+            # Fire and forget the atuin history end command to avoid blocking the shell during a potential sync.
+            $process = New-Object System.Diagnostics.Process
+            $process.StartInfo.FileName = "atuin"
+            $process.StartInfo.Arguments = "history end --exit=$exitCode $durationArg -- $script:atuinHistoryId"
+            $process.StartInfo.UseShellExecute = $false
+            $process.StartInfo.CreateNoWindow = $true
+            $process.StartInfo.RedirectStandardInput = $true
+            $process.StartInfo.RedirectStandardOutput = $true
+            $process.StartInfo.RedirectStandardError = $true
+            $process.Start() | Out-Null
+            $process.StandardInput.Close()
+            $process.BeginOutputReadLine()
+            $process.BeginErrorReadLine()
 
-            $global:LASTEXITCODE = $exitCode
             $script:atuinHistoryId = $null
         }