v0.1.2

Fixed

• MasterKeys can now be used without also specifying passwords. Previously,
  using Auth::usm().with_master_keys() would fail validation requiring
  auth_password even though keys were already derived.

Documentation

• Significantly expanded rustdoc coverage across all modules with examples
• Added crate-level documentation sections for error handling, tracing,
  agent compatibility, and high-throughput SNMPv3 polling
• Improved examples to use test container credentials and RFC 5737 TEST-NET
  addresses