ci(release): fail the PSGallery check on a query error instead of assuming not-published

Now that Publish is gated only on this check (recovery-gap fix #33), a
Find-Module -ErrorAction SilentlyContinue returning $null was treated as
'not on gallery' for BOTH a genuine miss and a transient query failure — so a
network/PSGallery hiccup could trigger a blind publish attempt. Capture
-ErrorVariable: publish only on a clean miss (Find-Module records no error for a
genuine not-found, verified for new-version and never-published cases); on a
recorded error, throw so the run is visibly retryable.

Surfaced by CodeRabbit/Copilot during the YouTubeMusicPS rollout review.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: tablackburn

.github/workflows/PublishModuleToPowerShellGallery.yaml

@@ -74,10 +74,17 @@ jobs:
           VERSION: ${{ steps.version.outputs.version }}
         run: |
           $version = $env:VERSION
-          $published = Find-Module -Name {{ModuleName}} -RequiredVersion $version -Repository PSGallery -ErrorAction SilentlyContinue
+          $findError = $null
+          $published = Find-Module -Name {{ModuleName}} -RequiredVersion $version -Repository PSGallery -ErrorAction SilentlyContinue -ErrorVariable findError
           if ($published) {
             Write-Host "PSGallery version $version already exists"
             "exists=true" | Out-File -FilePath $env:GITHUB_OUTPUT -Append
+          } elseif ($findError) {
+            # Find-Module records no error when the version simply isn't on the gallery,
+            # so a recorded error means the query itself failed (transient/network). Don't
+            # treat that as "not published" (publishing is now gated only on this check) —
+            # fail so the run is visibly retryable instead of attempting a blind publish.
+            throw "PowerShell Gallery query failed for version ${version}: $($findError[0].Exception.Message)"
           } else {
             Write-Host "PSGallery version $version not found - will publish"
             "exists=false" | Out-File -FilePath $env:GITHUB_OUTPUT -Append