Add rule evaluation profiling to Rego

Normalized profile

What this task asks for

Add opt-in per-rule evaluation profiling to Rego results with profiling stats and diff helpers. Add opt-in rule evaluation profiling to Rego evaluations. Every rule entered during evaluation must appear, including rules that fail. When profiling is not enabled, Profile must be nil. SuccessRate(rule) returns Successes/Evals, 0 if untracked or zero evals (nil receiver: 0). OverallSuccessRate() returns aggregate Successes/Evals across all rules (nil receiver: 0). FailedRules() returns sorted rules with Evals > 0 and Successes = 0 (nil receiver: nil).