ci(windows): use shell: pwsh (PowerShell 7) — fixes GITHUB_ENV BOM corruption

Windows PowerShell 5.1's Out-File -Encoding utf8 prepends a UTF-8 BOM, corrupting the first
GITHUB_ENV line so CARGO_WORKSPACE_DIR silently never got set -> windows-reactor build.rs panic
-> CI build failed (runs 8765/8768). pwsh 7 writes UTF-8 without a BOM. Installed PowerShell 7.6.2
MSI on the runner and put C:\Program Files\PowerShell\7 on the daemon wrapper PATH so jobs find
pwsh; switched all windows.yml steps to shell: pwsh. (Reproduced locally with CARGO_WORKSPACE_DIR
set: the build is green in 2m37s — the BOM was the only issue.)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.gitea/workflows/windows.yml

@@ -5,8 +5,12 @@
 # The MSVC/WinUI/FFmpeg toolchain (cargo/rustup on ASCII paths, NASM, CMake, LLVM, FFmpeg,
 # CARGO_HOME, CMAKE_POLICY_VERSION_MINIMUM, …) is baked into the runner's daemon env. The one
 # per-checkout var is CARGO_WORKSPACE_DIR (windows-reactor's build.rs unwraps it + stages the
-# Windows App SDK NuGets/winmd under it) — set from GITHUB_WORKSPACE in a step (not job-level
-# env, where Gitea can't yet resolve the workspace path).
+# Windows App SDK NuGets/winmd under it) — set from GITHUB_WORKSPACE in a step.
+#
+# Steps use `shell: pwsh` (PowerShell 7) deliberately: Windows PowerShell 5.1's
+# `Out-File -Encoding utf8` prepends a UTF-8 BOM that corrupts the first GITHUB_ENV line (the
+# CARGO_WORKSPACE_DIR var silently never gets set -> reactor build.rs panics). pwsh writes no BOM.
+# The runner's daemon wrapper puts C:\Program Files\PowerShell\7 on PATH so the job finds pwsh.
 name: windows
 
 on:
@@ -35,7 +39,7 @@ jobs:
       - uses: actions/checkout@v4
 
       - name: Configure + toolchain versions
-        shell: powershell
+        shell: pwsh
         run: |
           "CARGO_WORKSPACE_DIR=$env:GITHUB_WORKSPACE" | Out-File -FilePath $env:GITHUB_ENV -Append -Encoding utf8
           rustc --version
@@ -44,17 +48,17 @@ jobs:
           Write-Output "workspace: $env:GITHUB_WORKSPACE"
 
       - name: Build
-        shell: powershell
+        shell: pwsh
         run: cargo build -p punktfunk-client-windows
 
       - name: Clippy (-D warnings)
-        shell: powershell
+        shell: pwsh
         run: cargo clippy -p punktfunk-client-windows --all-targets -- -D warnings
 
       - name: Rustfmt check
-        shell: powershell
+        shell: pwsh
         run: cargo fmt -p punktfunk-client-windows -- --check
 
       - name: Test
-        shell: powershell
+        shell: pwsh
         run: cargo test -p punktfunk-client-windows

scripts/ci/setup-windows-runner.ps1

@@ -93,7 +93,7 @@ $env:RUSTUP_HOME = "C:\Users\Public\.rustup"
 $env:CMAKE_POLICY_VERSION_MINIMUM = "3.5"
 $env:LIBCLANG_PATH = "C:\Program Files\LLVM\bin"
 $env:FFMPEG_DIR = "C:\Users\Public\ffmpeg"
-$env:PATH = "C:\Users\Public\.cargo\bin;C:\nvm4w\nodejs;C:\Program Files\NASM;C:\Program Files\CMake\bin;C:\Program Files\LLVM\bin;C:\Users\Public\ffmpeg\bin;" + $env:PATH
+$env:PATH = "C:\Program Files\PowerShell\7;C:\Users\Public\.cargo\bin;C:\nvm4w\nodejs;C:\Program Files\NASM;C:\Program Files\CMake\bin;C:\Program Files\LLVM\bin;C:\Users\Public\ffmpeg\bin;" + $env:PATH
 Set-Location "C:\Users\Public\act-runner"
 # cmd-level redirect (>>, 2>&1) keeps the daemon's native stderr out of PowerShell's error stream.
 & cmd /c "act_runner.exe daemon --config config.yaml >> runner.log 2>&1"