Improves 'Update samples' workflow. Closes #700 (#747)

## 🎯 Aim

This PR updates 'Update Sample' workflow to include sample stats in the
PR body.

## 📷 Result

<img width="725" height="333" alt="image"
src="https://github.com/user-attachments/assets/c2bf2a3b-c470-4f66-8f04-0f1bd5f0d397"
/>


## ✅ What was done

- [X] generated sample stats, JSON validation and injected in PR
description

## 🔗 Related issue

Closes: #700

Author: Saurabh7019

.github/workflows/update-samples.yml

@@ -46,15 +46,29 @@ jobs:
       - run: |
           dir
 
-      - run: .\scripts\prepare-sample-data.ps1 -workspacePath "${{ github.workspace }}"
+      - name: Generate sample data
+        run: .\scripts\prepare-sample-data.ps1 -workspacePath "${{ github.workspace }}"
+        shell: pwsh
+
+      - name: Read statistics
+        id: stats
+        run: |
+          $delimiter = "EOF_STATS_$(Get-Random)"
+          $stats = Get-Content sample-stats.txt -Raw
+          "STATS<<$delimiter" >> $env:GITHUB_OUTPUT
+          $stats >> $env:GITHUB_OUTPUT
+          $delimiter >> $env:GITHUB_OUTPUT
+          Remove-Item sample-stats.txt
         shell: pwsh
-        continue-on-error: true
 
       - name: Create Pull Request
         uses: peter-evans/create-pull-request@v5
         with:
           commit-message: Updates sample data
           branch: update-sample-data
           title: Sample data update
-          body: Automated check and update of SPFx extensions and webparts samples data and aces sample data.
+          body: |
+            Automated check and update of SPFx extensions and webparts samples data and aces sample data.
+            
+            ${{ steps.stats.outputs.STATS }}
 ...

scripts/prepare-sample-data.ps1

@@ -185,5 +185,50 @@ $orderedSampleModel = [ordered]@{}
 foreach ($Item in ($sampleModel.GetEnumerator() | Sort-Object -Property Key)) {
     $orderedSampleModel[$Item.Key] = $Item.Value
 }
-New-Object -TypeName psobject -Property $orderedSampleModel | ConvertTo-Json -Depth 10 | Out-File "$workspacePath\data\sp-dev-fx-samples.json"
+
+$jsonOutput = New-Object -TypeName psobject -Property $orderedSampleModel | ConvertTo-Json -Depth 10
+
+try {
+    $null = ConvertFrom-Json -InputObject $jsonOutput -ErrorAction Stop
+    Write-Output "`nJSON validation passed"
+}
+catch {
+    Write-Error "`nGenerated JSON is invalid: $($_.Exception.Message)"
+    exit 1
+}
+
+$jsonOutput | Out-File "$workspacePath\data\sp-dev-fx-samples.json"
+
+$totalSamples = $samples.Count
+$statsByRepo = $samples | Group-Object -Property sampleGallery | Sort-Object Name
+
+$statsLines = @()
+$statsLines += '## Sample Data Summary'
+$statsLines += ''
+$statsLines += '✅ **JSON Validation:** Passed'
+$statsLines += ''
+$statsLines += "**Total Samples:** $totalSamples"
+$statsLines += ''
+$statsLines += '### Breakdown by Repository'
+
+foreach ($stat in $statsByRepo) {
+    $statsLines += "- **$($stat.Name):** $($stat.Count)"
+}
+
+$statsContent = $statsLines -join "`n"
+
+# temp output for PR body; will be deleted after PR is raised
+$statsContent | Out-File "$workspacePath\sample-stats.txt" -Encoding utf8
+
+if ($env:GITHUB_STEP_SUMMARY) {
+    $statsContent | Out-File $env:GITHUB_STEP_SUMMARY -Encoding utf8
+    Write-Output "Statistics written to GitHub Actions summary"
+}
+
+Write-Output "`nSample data update complete: $totalSamples total samples`n"
+foreach ($stat in $statsByRepo) {
+    Write-Output "  $($stat.Name): $($stat.Count)"
+}
+
+exit 0