ci(lint): probe multiple Python launcher locations for SYSTEM runner

act_runner SYSTEM context may not have py.exe or python.exe in PATH. Try a list of common install paths (C:\Python3XX, Program Files, LocalAppData) and allow override via CI_PYTHON_LAUNCHER env var.

.gitea/workflows/lint.yml

@@ -108,8 +108,40 @@ jobs:
             if (Test-Path $env:VENV_DIR) {
               Remove-Item $env:VENV_DIR -Recurse -Force
             }
-            $launcher = (Get-Command py.exe -ErrorAction Stop).Source
+
-            & $launcher -3.11 -m venv $env:VENV_DIR
+            # Find a usable Python launcher. act_runner runs as SYSTEM and may
+            # not have py.exe / python.exe in PATH; try common locations.
+            # Override via $env:CI_PYTHON_LAUNCHER if installed elsewhere.
+            $candidates = @()
+            if ($env:CI_PYTHON_LAUNCHER) { $candidates += $env:CI_PYTHON_LAUNCHER }
+            $candidates += @(
+              'py.exe',
+              'python.exe',
+              'C:\Python311\python.exe',
+              'C:\Python312\python.exe',
+              'C:\Python313\python.exe',
+              "$env:LOCALAPPDATA\Programs\Python\Python311\python.exe",
+              "$env:LOCALAPPDATA\Programs\Python\Python312\python.exe",
+              'C:\Program Files\Python311\python.exe',
+              'C:\Program Files\Python312\python.exe',
+              'C:\Program Files\Python313\python.exe'
+            )
+            $launcher = $null
+            foreach ($c in $candidates) {
+              $cmd = Get-Command $c -ErrorAction SilentlyContinue
+              if ($cmd) { $launcher = $cmd.Source; break }
+            }
+            if (-not $launcher) {
+              throw "No Python launcher found. Install Python 3.11+ system-wide or set CI_PYTHON_LAUNCHER. Tried: $($candidates -join ', ')"
+            }
+            Write-Host "Bootstrapping venv with: $launcher"
+
+            if ($launcher -like '*py.exe') {
+              & $launcher -3.11 -m venv $env:VENV_DIR
+            }
+            else {
+              & $launcher -m venv $env:VENV_DIR
+            }
             if ($LASTEXITCODE -ne 0) { throw "venv creation failed" }
           }