Add --indentation to bundle and upgrade

[jviotti]

Signed-off-by: Juan Cruz Viotti jv@jviotti.com

[augmentcode]

🤖 Augment PR Summary

Summary: This PR adds configurable JSON output indentation to the bundle and upgrade commands.

Changes:

• Registers --indentation/-n <spaces> for both commands.
• Passes the chosen indentation width to their prettify output calls.
• Extends indentation parsing to reject empty, non-numeric, and out-of-range values.
• Adds a dedicated CLI error and maps it to invalid-argument exit status.
• Updates command help and user documentation with the new option.
• Adds bundle/upgrade formatting tests and invalid-indentation coverage across commands.

Technical notes: The default remains two spaces, and zero is accepted as a non-negative indentation width.

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