Add OpenTelemetry security rule instrumentation

[hardbyte]

Summary

• add a SecurityRuleMetadata helper and expose it from the Policy trait so policies can describe their semantic attributes
• emit tracing events that populate the OpenTelemetry security rule fields when policies are evaluated
• cover the metadata helper with a unit test to ensure all semantic fields are preserved

Testing

• cargo test

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https://chatgpt.com/codex/tasks/task_b_68f196a675448329a69008f3a079048c

[Copilot]

Pull Request Overview

This PR adds OpenTelemetry security rule instrumentation to the permission checking framework. It introduces a metadata system for policies to describe their semantic attributes and emits structured tracing events during policy evaluation.

• Adds SecurityRuleMetadata helper to expose OpenTelemetry semantic fields
• Integrates tracing events into the policy evaluation process with security rule attributes
• Includes unit test coverage for the metadata builder functionality

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[hardbyte]

     Running benches/permission_checker.rs (target/release/deps/permission_checker-0c945ef4500025a5)
Gnuplot not found, using plotters backend
permission_checker_evaluate_access/trailing_allow/1
                        time:   [374.21 ns 394.24 ns 413.61 ns]
permission_checker_evaluate_access/all_deny/1
                        time:   [426.20 ns 465.38 ns 524.00 ns]
Found 5 outliers among 100 measurements (5.00%)
  4 (4.00%) high mild
  1 (1.00%) high severe
permission_checker_evaluate_access/trailing_allow/4
                        time:   [1.1045 µs 1.1531 µs 1.2027 µs]
Found 2 outliers among 100 measurements (2.00%)
  1 (1.00%) high mild
  1 (1.00%) high severe
permission_checker_evaluate_access/all_deny/4
                        time:   [989.76 ns 1.0377 µs 1.0904 µs]
Found 2 outliers among 100 measurements (2.00%)
  2 (2.00%) high mild
permission_checker_evaluate_access/trailing_allow/16
                        time:   [3.4887 µs 3.7212 µs 3.9558 µs]
Found 1 outliers among 100 measurements (1.00%)
  1 (1.00%) high mild
permission_checker_evaluate_access/all_deny/16
                        time:   [3.5392 µs 3.6936 µs 3.8537 µs]
Found 2 outliers among 100 measurements (2.00%)
  2 (2.00%) high mild
permission_checker_evaluate_access/trailing_allow/64
                        time:   [14.755 µs 15.321 µs 15.859 µs]
Found 4 outliers among 100 measurements (4.00%)
  4 (4.00%) low mild
permission_checker_evaluate_access/all_deny/64
                        time:   [15.003 µs 15.799 µs 16.594 µs]
Found 12 outliers among 100 measurements (12.00%)
  3 (3.00%) low mild
  9 (9.00%) high mild