chore(scripts): archive PowerShell scripts superseded by the Python CLI

Move 16 .ps1 files to scripts/archived/ — they have no live caller:

- 10 pure shims (New-BuildVM, Remove-BuildVM, Cleanup-OrphanedBuildVMs,
  Wait-VMReady, Invoke-RemoteBuild, Get-BuildArtifacts, Watch-DiskSpace,
  Watch-RunnerHealth, Get-CIJobSummary, Invoke-CIJob) that only forwarded
  to `ci_orchestrator`; the live Gitea composite action now calls
  `python -m ci_orchestrator job` directly.
- 6 Phase-C host tools reimplemented natively in Python (Start-BurnInTest
  [+ -Linux], Test-CapacityBurnIn → bench; Test-Smoke → smoke run;
  Validate-HostState → validate host; Set-CIGuestCredential → creds set).

Add scripts/archived/README.md mapping each file to its `ci` replacement,
and exempt scripts/archived/ from the PSScriptAnalyzer lint job.

Kept (still used / not yet ported): Register-CIScheduledTasks,
Backup-CITemplate, Invoke-RetentionPolicy, Set-TemplateSharedFolders,
Test-CIGuestWinRM, the e2e build harnesses, and all template/ guest
provisioning scripts.

.gitea/workflows/lint.yml

@@ -61,6 +61,9 @@ jobs:
               Invoke-ScriptAnalyzer -Path $_ -Recurse -Settings $settings -Severity Error,Warning
             }
           }
+          # scripts/archived/ holds frozen .ps1 superseded by the Python CLI
+          # (kept for history only) — exempt from lint.
+          $results = $results | Where-Object { $_.ScriptPath -notmatch '[\\/]archived[\\/]' }
 
           if ($results) {
             $results | Format-Table -AutoSize