Add `wp datamachine auth` CLI commands (connect/disconnect/config/status)

[chubes4]

Summary

The auth abilities already exist in core (datamachine/get-auth-status, datamachine/disconnect-auth, datamachine/save-auth-config) but there's no CLI surface for them. Need a wp datamachine auth command.

Proposed subcommands

wp datamachine auth status [<handler_slug>]

• No arg: show table of all registered auth providers with configured/authenticated status
• With arg: show detailed status for one provider

wp datamachine auth connect <handler_slug>

• For OAuth providers (Twitter, Instagram, Facebook, Reddit, Threads): calls get-auth-status ability which returns oauth_url, prints it for the user to click in browser. Existing callback handlers complete the flow.
• For non-OAuth providers (Bluesky): accepts --config flags directly (e.g. --handle=x --app-password=y), calls save-auth-config ability.

wp datamachine auth disconnect <handler_slug>

• Wraps disconnect-auth ability. Clears stored account data.

wp datamachine auth config <handler_slug>

• Wraps save-auth-config ability. Saves API keys / client credentials.
• Shows required config fields via get_config_fields() on the provider.

Context

• All three abilities are in inc/Abilities/AuthAbilities.php
• Auth providers register via datamachine_auth_providers filter
• Base classes: BaseAuthProvider, BaseOAuth1Provider, BaseOAuth2Provider in inc/Core/OAuth/
• Each provider implements get_authorization_url() and handle_oauth_callback() for OAuth flow
• New command class should go in inc/Cli/Commands/AuthCommand.php extending BaseCommand
• Register in Bootstrap.php as wp datamachine auth

Current state

The data-machine-socials plugin has per-platform status subcommands (e.g. wp datamachine-socials twitter status) but these are convenience wrappers — the core auth management belongs in data-machine.