5.3 Complete auto-accept through trusted-client grants

[marwannettour]

Parent epic: #311

Summary

Finalize controlled auto-accept behavior based on grants.

Requirements

• Allow trusted clients to request automatic join, inventory, or synchronization only when grants permit it.
• Use AutoJoin as the minimum grant for JoinOnly.
• Use AutoInventory as the minimum grant for Inventory.
• Use AutoSynchronize as the minimum grant for Synchronize.
• Treat stronger grants as including weaker actions where appropriate.

Acceptance criteria

• Auto-accept only happens with a valid grant.
• Stronger grants cover weaker requested modes.
• Profile-scoped grants are enforced.