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/Watch-RunnerHealth.ps1

@@ -49,7 +49,17 @@ param(
 
     [string] $StateDir = 'F:\CI\State',
 
-    [string] $WebhookUrl = ''
+    [string] $WebhookUrl = '',
+
+    # Optional Gitea API runner-online verification.
+    # When $GiteaUrl is non-empty and the act_runner service is Running, this script
+    # queries GET $GiteaUrl/api/v1/admin/runners and warns if zero runners are online.
+    # Requires an admin Personal Access Token stored in Windows Credential Manager
+    # under $GiteaCredentialTarget (same module: CredentialManager).
+    # Silently skipped if GiteaUrl is empty or the credential is unavailable.
+    [string] $GiteaUrl = '',
+
+    [string] $GiteaCredentialTarget = ''
 )
 
 Set-StrictMode -Version Latest
@@ -103,6 +113,40 @@ if (-not $svc) {
 
 if ($svc.Status -eq 'Running') {
     Write-Host "[RunnerHealth] $ServiceName is Running — OK"
+
+    # ── Optional Gitea runner-online API check ────────────────────────────────
+    if ($GiteaUrl -ne '') {
+        $pat = $null
+        if ($GiteaCredentialTarget -ne '') {
+            try {
+                $cred = Get-StoredCredential -Target $GiteaCredentialTarget -ErrorAction Stop
+                $pat  = $cred.GetNetworkCredential().Password
+            } catch {
+                Write-Warning "[RunnerHealth] Could not load Gitea PAT from '$GiteaCredentialTarget': $_"
+            }
+        }
+        if ($pat) {
+            try {
+                $apiUrl  = "$($GiteaUrl.TrimEnd('/'))/api/v1/admin/runners"
+                $runners = Invoke-RestMethod -Uri $apiUrl `
+                               -Headers @{ Authorization = "token $pat" } `
+                               -Method Get -TimeoutSec 10 -ErrorAction Stop
+                $online  = @($runners | Where-Object { $_.online -eq $true })
+                if ($online.Count -gt 0) {
+                    Write-Host "[RunnerHealth] Gitea API: $($online.Count) runner(s) online — OK"
+                } else {
+                    $msg = "Gitea API ($apiUrl) reports 0 online runners. " +
+                           "$ServiceName service is Running — possible registration issue."
+                    Write-Warning "[RunnerHealth] $msg"
+                    Write-CIEvent -EventId 1005 -EntryType Warning -Message $msg
+                    Send-Webhook -Content "[WARNING] CI Runner Alert -- $msg"
+                }
+            } catch {
+                Write-Warning "[RunnerHealth] Gitea API check failed: $_"
+            }
+        }
+    }
+
     exit 0
 }