fix: if node_pkg_workspaces unbound, return empty string

[ryuwd]

No description provided.

[Copilot]

Pull Request Overview

This PR fixes potential "unbound variable" errors in a shell script by adding proper parameter expansion defaults for the node_pkg_workspaces array variable. The fix ensures the script continues to work when node_pkg_workspaces is not initialized or is empty.

• Adds default empty values using ${array[@]:-} syntax for array expansions
• Adds default value of 0 for array length checks using ${#array[@]:-0} syntax

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