[script][sew] Add tool validation, pin counter, and holding error handler

[MahtraDR]

Summary

• Tool validation in swap_tool: exits gracefully if the requested tool was not actually obtained, preventing silent failures mid-craft
• "You must be holding" error handler: catches cases where the required tool is not in hand and exits cleanly instead of looping
• Pin poke counter: tracks pin usage throughout the crafting session and reports the count in the completion message
• Prefixed error messages: all sew error messages now start with sew: for easier identification in scrollback
• Detailed completion message: reports recipe name, chapter, noun, pin pokes, and finish mode

All changes are additive -- the existing engaged-while-crafting handler is preserved.

Test plan

• Normal sewing session completes with detailed summary including pin count
• Tool not found scenario: script exits with clear error message
• "Not holding" scenario: script exits cleanly instead of looping
• Engaged while crafting: existing retreat + pause behavior still works

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