Module registries 

Built-in ToolRegistry implementations.

• DynamicRegistry supports runtime tool activation/deactivation.
• GroupedRegistry organizes tools into named groups with group-level activation/deactivation.

Both use RwLock for interior mutability, enabling shared &self access.

Structs

AdaptiveRegistry

A tool registry that automatically limits the number of visible tools based on the configured model tier.

DynamicRegistry

A mutable tool registry supporting runtime add/remove/toggle.

GroupedRegistry

A tool registry that organizes tools into named groups with group-level activation and deactivation.

TierLimits

Per-tier tool limits.