Improve UI startup after runspace overhaul (#5056)

* perf: keep UI startup responsive

* test: make favicon checks runner-safe

* fix: qualify favicon visibility state

* test: isolate favicon visibility fixture

* fix: enforce total favicon deadline

* fix: address favicon review feedback

* fix: recognize disabled SSH firewall rule

* perf: restore favicon download throughput

* docs: allow public PR review uploads

* perf: restore overlapping favicon loading

pester/xaml.Tests.ps1

@@ -411,6 +411,7 @@ Describe "XAML and sync wiring" {
             "Buttons",
             "PSScriptRoot",
             "version",
+            "IsLocalCompile",
             "winutildir",
             "logPath",
             "transcriptPath",