nice-to-have: implement all 6 tier items

- Get-CIJobSummary.ps1: already present with full implementation (marked done)
- Get-BuildArtifacts.ps1: add -JobId/-Commit params; Write-ArtifactManifest writes
  manifest.json (name, size, sha256, commit, jobId) after both Linux and Windows
  artifact collection branches
- Invoke-CIJob.ps1: add -GuestCPU/-GuestMemoryMB params; insert post-clone VMX
  override block (numvcpus/memsize rewrite) before vmrun start; pass -JobId/-Commit
  to Get-BuildArtifacts calls
- Watch-RunnerHealth.ps1: add -GiteaUrl/-GiteaCredentialTarget params; optional
  GET /api/v1/admin/runners check in Running branch warns if 0 online runners
- Install-CIToolchain-WinBuild2025.ps1: fill SHA256 hashes for Python 3.13.3,
  7-Zip 26.01, Node.js 22.14.0, dotnet-install.ps1
- Measure-CIBenchmark.ps1: add deltaKB field (linked-clone disk footprint in KB)
  measured post-clone; added to result object and summary Format-Table

scripts/Measure-CIBenchmark.ps1

@@ -104,6 +104,7 @@ for ($i = 1; $i -le $Iterations; $i++) {
         ip      = $null
         winrm   = $null
         destroy = $null
+        deltaKB = $null
         vmIP    = $null
         error   = $null
     }
@@ -122,6 +123,16 @@ for ($i = 1; $i -le $Iterations; $i++) {
         $t.clone = [math]::Round($sw.Elapsed.TotalSeconds, 2)
         Write-Host "[bench] clone: $($t.clone)s"
 
+        # Measure linked-clone disk footprint
+        try {
+            $cloneSizeBytes = (Get-ChildItem -Path $cloneDir -Recurse -File -ErrorAction Stop |
+                Measure-Object -Property Length -Sum).Sum
+            $t.deltaKB = [math]::Round($cloneSizeBytes / 1KB, 0)
+            Write-Host "[bench] clone size: $($t.deltaKB) KB"
+        } catch {
+            Write-Warning "[bench] Could not measure clone size: $_"
+        }
+
         # ── Phase: start ──────────────────────────────────────────────────────
         Write-Host "[bench] Starting VM..."
         $sw.Restart()
@@ -191,6 +202,7 @@ for ($i = 1; $i -le $Iterations; $i++) {
         winrmSec     = $t.winrm
         destroySec   = $t.destroy
         totalBootSec = $totalBootSec
+        deltaKB      = $t.deltaKB
         vmIP         = $t.vmIP
         error        = $t.error
     }
@@ -217,6 +229,7 @@ $results | Format-Table @(
     @{ L = 'WinRM(s)';   E = { $_.winrmSec } }
     @{ L = 'Destroy(s)'; E = { $_.destroySec } }
     @{ L = 'Boot total'; E = { $_.totalBootSec } }
+    @{ L = 'Delta(KB)';  E = { $_.deltaKB } }
     @{ L = 'IP';         E = { $_.vmIP } }
     @{ L = 'Error';      E = { $_.error } }
 ) -AutoSize