feat(pgpm): add -w alias for --workspace flag on upgrade command

[pyramation]

Summary

Adds -w as a short alias for --workspace on the pgpm upgrade command, matching the pattern used by -i/--interactive.

# These are now equivalent:
pgpm upgrade --workspace
pgpm upgrade -w

Review & Testing Checklist for Human

• Verify pgpm upgrade -w works the same as pgpm upgrade --workspace in a real workspace

Test plan:

cd /path/to/pgpm/workspace
pgpm upgrade -w  # Should upgrade all modules across workspace

Notes

• Requested by: Dan Lynch (@pyramation)
• Session: https://app.devin.ai/sessions/95ea22c05e164e99ac7770c57aed8b2d

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