re-clone when git reports dubious ownership on the working copy

a clone first created from an elevated prompt is owned by Administrators; a
later normal-user run then fails every git op with 'dubious ownership'
(exit 128), which the launcher misreported as an auth error. detect that
case and remove the clone for a clean re-clone.

scripts/Start-ShopDBDev.ps1

@@ -91,6 +91,23 @@ function Clear-InterruptedRun {
 		Write-Host "==> Removing incomplete clone at $Target" -ForegroundColor Cyan
 		Remove-Item -Path $Target -Recurse -Force
 	}
+
+	# A clone created by an elevated (Administrator) run is owned by
+	# BUILTIN\Administrators; a later non-elevated run then trips git's
+	# "detected dubious ownership" guard and every git op fails with exit 128.
+	# That stale clone is effectively unusable for this user, so detect the
+	# condition and remove it here for a clean re-clone rather than surfacing a
+	# misleading auth error later.
+	if (Test-Path (Join-Path $Target '.git')) {
+		$previous = $ErrorActionPreference
+		$ErrorActionPreference = 'Continue'
+		try { $probe = git -C $Target rev-parse --is-inside-work-tree 2>&1 } catch { $probe = "$_" }
+		finally { $ErrorActionPreference = $previous }
+		if ($probe -match 'dubious ownership') {
+			Write-Host "==> Removing clone with mismatched ownership at $Target (was it created from an elevated prompt?)" -ForegroundColor Cyan
+			Remove-Item -Path $Target -Recurse -Force
+		}
+	}
 }
 
 # Plain https URL. No token in the URL: Git Credential Manager injects the