Variable maskedEmailStateValidationPluginConst

Validates MaskedEmail state transition constraints.

This plugin enforces FastMail's state machine rules for MaskedEmail objects:

State Transition Rules:

• Once a MaskedEmail transitions from "pending" to any other state, it cannot be set back to "pending"
• Valid states: "pending", "enabled", "disabled", "deleted"
• State can transition: pending → enabled/disabled/deleted
• State can transition: enabled ⟷ disabled ⟷ deleted
• State cannot transition: enabled/disabled/deleted → pending

Automatic Transitions:

• Pending addresses automatically become "enabled" when they receive their first message
• Pending addresses are automatically deleted after 24 hours if unused

This validation prevents invalid state transitions during updates, catching errors before they reach the server.