Enhance SandwichReminder-AutoOrder feature with direct checkout navigation and improved logic

- Added new configuration options for direct checkout navigation, including `useDirectCheckoutNavigation`, `checkoutPath`, and `checkoutOpenDelayMs`.
- Updated the auto-order flow to navigate directly to the checkout page, skipping the mini-cart and date/time steps.
- Improved keyboard automation logic for item remark and order confirmation processes.
- Removed the old SandwichAutoOrder.ps1 file as its functionality has been integrated into SandwichReminder-AutoOrder.ps1.
- Introduced a new runner-launcher.vbs to start the runner.ps1 without a visible console window, ensuring WinForms dialogs can appear.
- Implemented a mutex mechanism in runner.ps1 to prevent concurrent execution of the same feature.

internal/runner.ps1

@@ -11,7 +11,6 @@ $script:InternalRoot = $PSScriptRoot   # runner.ps1 lives in internal\
 . (Join-Path $InternalRoot 'lib\NetworkUtils.ps1')
 . (Join-Path $InternalRoot 'lib\ToastHelper.ps1')
 . (Join-Path $InternalRoot 'lib\PromptHelper.ps1')
-. (Join-Path $InternalRoot 'lib\SandwichAutoOrder.ps1')
 . (Join-Path $InternalRoot 'lib\Config.ps1')
 
 Write-Log -Level Info -Message '────── Runner started ──────' -Feature 'Runner'
@@ -38,7 +37,23 @@ foreach ($featureKey in $config.features.Keys) {
         continue
     }
 
+    # Per-feature mutex: prevents two concurrent runner instances from executing
+    # the same feature simultaneously (e.g. if the previous run is still in progress).
+    $mutexName = "Global\PSAutomation-Feature-$featureKey"
+    $mutex = $null
+    $mutexAcquired = $false
+
     try {
+        $mutex = New-Object System.Threading.Mutex($false, $mutexName)
+        $mutexAcquired = $mutex.WaitOne(0)   # non-blocking: skip if already locked
+
+        if (-not $mutexAcquired) {
+            Write-Log -Level Warn `
+                -Message "Feature '$featureKey' skipped: another instance is still running." `
+                -Feature 'Runner'
+            continue
+        }
+
         # Dot-source the feature — defines $FeatureMeta and Invoke-Feature in local scope.
         # Each iteration overwrites Invoke-Feature, which is fine because we call it immediately.
         $ErrorActionPreference = 'Stop'
@@ -61,6 +76,12 @@ foreach ($featureKey in $config.features.Keys) {
     }
     finally {
         $ErrorActionPreference = 'Stop'
+        if ($mutexAcquired -and $null -ne $mutex) {
+            try { $mutex.ReleaseMutex() } catch {}
+        }
+        if ($null -ne $mutex) {
+            try { $mutex.Dispose() } catch {}
+        }
     }
 }