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/Get-BuildArtifacts.ps1

@@ -65,7 +65,13 @@ param(
 
     # Persistent known_hosts file for SSH calls (CI jobs).
     # Empty string (default) = permissive mode (StrictHostKeyChecking=no, UserKnownHostsFile=NUL).
-    [string] $SshKnownHostsFile = ''
+    [string] $SshKnownHostsFile = '',
+
+    # Optional job ID and commit SHA written into manifest.json.
+    # When either is non-empty a manifest.json is written to $HostArtifactDir
+    # listing all collected files with name, size, and SHA256.
+    [string] $JobId  = '',
+    [string] $Commit = ''
 )
 
 Set-StrictMode -Version Latest
@@ -73,6 +79,34 @@ $ErrorActionPreference = 'Stop'
 
 Import-Module (Join-Path $PSScriptRoot '_Common.psm1') -Force
 
+# ── Helper: write artifact manifest ─────────────────────────────────────────
+function Write-ArtifactManifest {
+    param([string] $Dir, [string] $JobId, [string] $Commit)
+    $files = @(Get-ChildItem -Path $Dir -Recurse -File -ErrorAction SilentlyContinue |
+        Where-Object { $_.Name -ne 'manifest.json' })
+    $fileEntries = foreach ($f in $files) {
+        [pscustomobject]@{
+            name   = $f.FullName.Substring($Dir.TrimEnd('\', '/').Length).TrimStart('\', '/')
+            size   = $f.Length
+            sha256 = (Get-FileHash $f.FullName -Algorithm SHA256).Hash.ToLower()
+        }
+    }
+    $manifest = [ordered]@{
+        ts     = (Get-Date -Format 'o')
+        jobId  = $JobId
+        commit = $Commit
+        files  = @($fileEntries)
+    }
+    $manifestPath = Join-Path $Dir 'manifest.json'
+    try {
+        $manifest | ConvertTo-Json -Depth 4 |
+            Set-Content -Path $manifestPath -Encoding UTF8 -Force -ErrorAction Stop
+        Write-Host "[Get-BuildArtifacts] Manifest written: $manifestPath ($($files.Count) file(s))"
+    } catch {
+        Write-Warning "[Get-BuildArtifacts] Could not write manifest.json: $_"
+    }
+}
+
 if ($GuestOS -eq 'Windows' -and $null -eq $Credential) {
     throw "Credential is required when GuestOS is Windows."
 }
@@ -103,6 +137,9 @@ if ($GuestOS -eq 'Linux') {
         throw "[Get-BuildArtifacts] No files found in $HostArtifactDir after SCP transfer."
     }
     Write-Host "[Get-BuildArtifacts] $($transferred.Count) file(s) collected from Linux guest."
+    if ($JobId -ne '' -or $Commit -ne '') {
+        Write-ArtifactManifest -Dir $HostArtifactDir -JobId $JobId -Commit $Commit
+    }
     return
 }
 
@@ -180,6 +217,9 @@ try {
     $sizeKB = [math]::Round($fileItem.Length / 1KB, 1)
 
     Write-Host "[Get-BuildArtifacts] Artifact collected: $hostDestPath ($sizeKB KB)"
+    if ($JobId -ne '' -or $Commit -ne '') {
+        Write-ArtifactManifest -Dir $HostArtifactDir -JobId $JobId -Commit $Commit
+    }
     return $hostDestPath
 }
 finally {