Current State: Basic share links with read/write permissions.

Needed Improvements:

• Granular Permissions - Page-level, block-level, and property-level access
• UCAN Delegations - Cryptographic capability sharing (already have foundation)
• Role-Based Access - Owner, Admin, Editor, Commenter, Viewer
• Guest Access - Time-limited or usage-limited tokens
• Access Revocation - Ability to revoke shared access

interface Permission {
  resource: { type: 'workspace' | 'page' | 'block'; id: string };
  principal: string; // DID
  capabilities: ('read' | 'write' | 'admin' | 'share')[];
  constraints?: {
    expiry?: Date;
    maxUses?: number;
  };
  delegation: string; // UCAN proof chain
}