Workspace-level email sync policy: admin defaults + "contact-associated only" retention

Problem. Email sync settings (visibility, contact auto-creation, group/non-professional exclusions) are per mailbox, set by each user. Admins can't set defaults or enforce a policy. Twenty also imports and stores every message in the synced folders, whether or not it involves a CRM contact. In practice: • Personal and unrelated mail ends up in the database (bank alerts, newsletters, an earlier job's correspondence). It's readable through the API and MCP even though it never appears on a record. • A new user's first import, with auto-creation on, can create hundreds of junk People and Companies from their history before anyone can change the setting. We had to clean up 861 People and 48 Companies from one user's calendar. • Choosing Inbox + Sent doesn't filter much, since almost everything lands in the Inbox. Proposal. 1. Workspace sync policy in admin settings. Defaults for visibility, contact auto-creation and exclusions, app…