Bulk invite users

Creates multiple invites at once (max 50 per request).

Returns counts of successful and failed invites (rate-limited invites count as failed), a rate_limited flag, and per-invite results.

Invites are processed sequentially. Individual failures don't stop remaining invites. If rate limit is exceeded, processing stops and remaining invites are marked as rate-limited.

Available roles:

• organization_manager - Organization manager with manager access to specified projects
• project_manager - Organization user with manager access to specified projects
• project_user - Organization user with user access to specified projects
• project_viewer - Organization user with viewer access to specified projects

Common failure reasons:

• validation_error - Invalid email, already a member, or other validation issues
• create_action_error - Business rule violations (plan limits, blacklisted user)
• rate_limited - Rate limit exceeded during processing
• system_error - Unexpected system errors

Note: Invalid project IDs are automatically filtered out. Emails are automatically lowercased.