Use destructive hints on JSON specs to provide confirmation DX

Adding hints to APIs that are potentially destructive was handled in https://github.com/elastic/schemas-js/issues/25. The hints will be used by MCP and Agent Builder, so we should add a corresponding feature to the CLI.

Proposed experience:

- By default, destructive actions wait for interactive confirmation: `This is a potentially destructive action. Do you want to continue? [y/N]`
- Confirmation step is skipped if any of the following are true:
- `--yes` CLI flag is used
- `YES=true` env var is set
- `require_confirmation: false` is set in the config file
- allow/blocklist filtering configuration (`commands.allowed`, `commands.blocked`) is extended to include `commands.block_destructive` that takes a boolean.
- if `true`, destructive commands are implicitly added to `commands.blocked`
- if `false` or unset, destructive commands are allowed
- if `false` but a `commands.allowed` list is also present, the option is ignored to avoid accidentally making the allowlist overly permissive