Speed up runspace and tab initialization (#4793)

* Add startup performance tracing

* Lazy initialize non-default tabs

* Render install app entries incrementally

* Defer and cache toggle status checks

* Clean up runspace invocation ownership

* Defer GUI runspace pool startup

* Defer status taskbar asset rendering

* Record final speed verification

* Fix deferred install render timer callback

* Add dispatcher smoke coverage for install rendering

* Replace install render timer with dispatcher callbacks

* Gate performance tracing behind compile switch

* Clean up analyzer warnings in speed changes

* Speed up runspace and tab initialization

functions/private/Close-WinUtilRunspacePool.ps1

@@ -0,0 +1,18 @@
+function Close-WinUtilRunspacePool {
+    if ($null -eq $sync -or -not $sync.ContainsKey("runspace") -or $null -eq $sync.runspace) {
+        return
+    }
+
+    try {
+        if ($sync.runspace.RunspacePoolStateInfo.State -notin @(
+            [System.Management.Automation.Runspaces.RunspacePoolState]::Closed,
+            [System.Management.Automation.Runspaces.RunspacePoolState]::Closing,
+            [System.Management.Automation.Runspaces.RunspacePoolState]::Broken
+        )) {
+            $sync.runspace.Close()
+        }
+    } finally {
+        $sync.runspace.Dispose()
+        $sync.Remove("runspace")
+    }
+}