CLI: batch-specific help text on send batch

Features

• CLI: batch-specific help text on send batch
• CLI: inline valid values in option errors
• Docs: rewrite batch-operations page with CLI examples and accurate API fields
• Docs: rewrite agent coordination page
• Docs: --variables examples and CLI tabs on templates page
• Docs: consent check responses, classify response shape, and safety settings

Fixes

• Billing: include monthly quota in budget response
• Analytics: return 404 for nonexistent segment in segment-check
• Threads: return 404 for bulk thread ops on nonexistent IDs
• Agentic mailbox proxy: preserve upstream 4xx status codes
• Safety: add missing per-threat action fields to SafetySettingsBody
• CLI: --template flag now says 'slug' not 'ID'
• Domains: sanitize error messages and add missing proxy routes
• Send simulate: include billing status in response
• Templates render: fix crash on unpublished templates and support slug lookup
• Docs: fix suppression/consent field names and add missing API params