ci: pin invariant globalization on the Windows gate

The runner reports en-US interactively, but its scheduled task inherits
en-SE (English/Sweden), whose decimal separator is a comma. That broke 40
tests across App/Core/Runtime/UI.Abstractions on number formatting alone
(expected "update:0.25", actual "update:0,25"). Set-Culture does not reach
a task running without a loaded user profile, and a build gate should not
depend on a machine's regional settings regardless.

Note for follow-up: this pins CI only. The underlying culture sensitivity is
real — a Swedish-locale player would see comma-formatted numbers in these
diagnostic strings.

.gitea/workflows/ci.yml

@@ -41,6 +41,15 @@ jobs:
 
       - name: Test (lane-filtered, streaming)
         shell: pwsh
+        env:
+          # The gate must not depend on the runner's regional settings. This
+          # box reports en-US interactively but the scheduled task inherits
+          # en-SE (English/Sweden, COMMA decimal separator), which broke 40
+          # tests across four projects on formatted numbers alone —
+          # e.g. expected "update:0.25", got "update:0,25". Set-Culture does
+          # not reach a task that runs without loading the user profile, so
+          # pin globalization for the test processes instead.
+          DOTNET_SYSTEM_GLOBALIZATION_INVARIANT: '1'
         run: |
           $ErrorActionPreference = 'Stop'
           $filter = 'Lane!=InstalledDat&Lane!=PreparedPackage&Lane!=Live&Lane!=Manual&Lane!=Windows&Lane!=Linux&Lane!=SystemFont&Purpose!=Diagnostic&Status!=KnownFailure'