storage: add delete-column command

[DasaDama]

Feature request

Add a storage delete-column command to the CLI.

Motivation

Deleting a column from a Storage table is a frequent operational task (e.g. across many projects in a telemetry org), but the CLI currently has no support for it — requiring direct Storage API calls or custom scripts as a workaround.

Proposed usage

kbagent storage delete-column --project NAME --table-id out.c-bucket.table --column column_name [--dry-run] [-y]

Expected behavior

• --dry-run prints what would be deleted without making any changes
• -y skips the confirmation prompt
• Support repeating --column for multiple columns in one call
• Consistent with existing delete-table command style

Current workaround

Direct HTTP call:

DELETE /v2/storage/tables/{tableId}/columns/{columnName}

🤖 Generated with Claude Code

[padak]

Thanks @DasaDama for the feature request! The storage delete-column command is now available in v0.19.0.