fix(workflows): use shell:powershell (PS 5.1) instead of pwsh; fix ciScriptsDir path

- All 3 workflows: pwsh -> powershell (host requires PS 5.1, not Core 7+)
- workflow-example.yml: replace GITHUB_WORKSPACE-relative ciScriptsDir with
  hardcoded host path; use SSH alias URL (host-clone mode) instead of HTTP
- docs: add WORKFLOW-AUTHORING.md reference for AI and developers

gitea/workflow-example.yml

@@ -47,17 +47,17 @@ jobs:
       # This script handles the entire VM lifecycle:
       #   clone → start → wait ready → build → collect artifacts → destroy
       - name: Build in ephemeral VM
-        shell: pwsh
+        shell: powershell
         run: |
           $ErrorActionPreference = 'Stop'
 
-          # Resolve the scripts directory relative to the checked-out repo.
-          # If your CI scripts are in a separate repo, adjust the path.
-          $ciScriptsDir = Join-Path $env:GITHUB_WORKSPACE 'scripts'
+          # CI scripts are at a fixed location on the runner host.
+          # Do NOT use $env:GITHUB_WORKSPACE — the CI system is in a separate repo.
+          $ciScriptsDir = 'N:\Code\Workspace\Local-CI-CD-System\scripts'
 
           & "$ciScriptsDir\Invoke-CIJob.ps1" `
             -JobId                 "${{ github.run_id }}-${{ github.run_attempt }}" `
-            -RepoUrl               "${{ github.server_url }}/${{ github.repository }}.git" `
+            -RepoUrl               "ssh://gitea-ci/${{ github.repository }}.git" `
             -Branch                "${{ github.ref_name }}" `
             -Commit                "${{ github.sha }}" `
             -Submodules `