fix: apply all FIX-TODO items (P0/P1/P2)

P0 bugs:
- Invoke-CIJob.ps1: skip --depth 1 when $Commit specified (shallow clone
  + checkout specific commit was silently failing)
- Get-BuildArtifacts.ps1: check .Length -eq 0 not rounded sizeKB (false
  fail on artifacts smaller than 50 bytes)
- build-nsis.yml: upgrade upload-artifact v3 -> v4 (v3 deprecated)

P0 security:
- Remove hardcoded default password CIBuild!ChangeMe2026 from all scripts,
  README, TODO; prompt Read-Host -AsSecureString at runtime instead
- Setup-TemplateVM.ps1: replace `net user $u $p /add` (password in argv /
  audit log 4688) with New-LocalUser + local ConvertTo-SecureString
- Prepare-TemplateSetup.ps1: save and restore WSMan AllowUnencrypted +
  TrustedHosts in finally block (was permanently mutating host WinRM config)
- Setup-TemplateVM.ps1: remove duplicate MaxMemoryPerShellMB (winrm set
  + Set-Item both setting same value)

P1 doc (stale Host-Only / VMnet11 era):
- Setup-TemplateVM.ps1: rewrite NETWORK REQUIREMENT block + final steps
  (system uses VMnet8 NAT permanently, not VMnet11 Host-Only)
- Invoke-CIJob.ps1 Phase 1 comment: correct network model
- ARCHITECTURE.md: remove Git from toolchain list (not installed); clarify
  zip-transfer rationale (no PAT in VM, not network isolation)
- BEST-PRACTICES.md: rewrite Step 8 as NAT topology verification

P1 minor:
- Invoke-RemoteBuild.ps1: remove wasted first New-Item (created then
  immediately removed and recreated)
- Wait-VMReady.ps1: remove unused $elapsed; simplify try/catch around
  native command (exit codes don't throw)
- Install-Runner.ps1: add deprecation notice pointing to Setup-Host.ps1

P2 operational:
- Add scripts/Cleanup-OrphanedBuildVMs.ps1 with -WhatIf support
- Get-BuildArtifacts.ps1 -IncludeLogs: add -Recurse (msbuild logs in subdir)
- Add gitea/workflows/lint.yml (PSScriptAnalyzer on .ps1 push/PR)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

scripts/Invoke-CIJob.ps1

@@ -190,11 +190,16 @@ $exitCode = 0
 
 try {
     # ── Phase 1: Clone repo on HOST ───────────────────────────────────────
-    # The build VM has no internet/LAN access (Host-Only network).
-    # Source is cloned here on the host, then copied into the VM via WinRM.
+    # Build VM is on VMnet8 NAT (internet OK for builds), but source is
+    # still cloned here and copied via WinRM zip to avoid injecting a PAT
+    # into the VM environment.
     Write-Host "`n[Phase 1/6] Cloning repository on host..."
     if (Test-Path $hostCloneDir) { Remove-Item $hostCloneDir -Recurse -Force }
-    $gitArgs = @('clone', '--depth', '1', '--branch', $Branch)
+    # Skip --depth 1 when a specific commit is requested: shallow clones
+    # only contain HEAD, so checkout of an older commit will fail.
+    $gitArgs = @('clone')
+    if ([string]::IsNullOrWhiteSpace($Commit)) { $gitArgs += @('--depth', '1') }
+    $gitArgs += @('--branch', $Branch)
     if ($Submodules) { $gitArgs += '--recurse-submodules' }
     $gitArgs += @($RepoUrl, $hostCloneDir)
     $ErrorActionPreference = 'Continue'