perf: add matched XMage runtime trial

[jackmaiorino]

What changed

Adds a bounded XMage-side matched-runtime benchmark adapter for the fixed Rally workload:

• deterministic seeded uniform-mirror policy and player
• benchmark runner with fail-closed configuration, workload, catalog, privacy, and classpath checks
• callback-level fixtures for pass, Blood, Bushwhacker, Chain payment/retarget, source-distinct actions, and trigger-order caching
• minimal ComputerPlayerRL integration needed to expose the audited callback surface

Why

This is the control-group side of the Rust kernel performance program. It exists only to produce a reproducible XMage denominator and parity transcript for the same seeded policy/workload. It is not an XMage feature expansion and it does not claim a Rust speedup.

Validation

• mandatory scripts/verify_all.sh pre-commit gate: PASS
• AIRL compile: PASS
• benchmark self-test: PASS
• focused regression mains: 23/23 PASS
• strict read-only catalog/configuration path exercise: PASS
• independent configuration/privacy/classpath audit: PASS
• independent fixed-Rally player/callback audit: PASS

A dirty local smoke run observed approximately 4.55 games/s, but that result is deliberately non-claiming because the source state was dirty and the formal paired protocol has not yet run. A cross-engine multiplier remains blocked until the Rust deadline mode and neutral transcript schemas are aligned.