feat(contracts): add admin-configurable transfer limits

[funds0033-cmyk]

Closes #96## Summary
This PR introduces configurable transfer limits that can be managed by an authorized administrator. Limits are persisted on-chain, validated before storage, and enforced throughout the contract while maintaining the existing security model.

Changes

• Added the set_limits(ConfiguredLimits) admin-only entrypoint protected by admin.require_auth().
• Implemented cooldown-gated limit updates with validation before persisting to instance storage.
• Added get_limits to retrieve configured limits, falling back to default values when no custom configuration exists.
• Updated create_transfer and get_transfers_paged to enforce the stored configurable limits.
• Introduced the InvalidLimits contract error for invalid configurations.
• Added the limits_changed event to emit successful limit updates.
• Added tests covering:
  • Successful admin updates
  • Authorization failures
  • Invalid limit configurations
  • Enforcement of configured limits
  • Uninitialized contract behavior
• Updated documentation for authorization, contract entrypoints, events, errors, storage, data types, testing, and CLI usage.

Validation

• Implementation completed on branch feat/authorized-setter-tunable-limits-93.
• Local cargo test could not be executed due to a local disk-space limitation. After freeing disk space, run:

  cargo test limits
  
  Closes #93