feat: complete Runtime protocol and durable operation semantics

[ZhiXiao-Lin]

Summary

• complete typed Runtime protocol identities, golden wire fixtures, and capability-driven conformance profiles
• add cross-process leases, durable request journaling, replay, crash-safe state writes, and generation reconciliation
• define and forward durable exec deadlines across provider boundaries
• add race, fault-injection, transition-matrix, recovery, stable, and MSRV verification gates

Validation

• the branch includes focused protocol, conformance, deterministic-fault, process-race, and general runtime coverage
• repository CI will run the stable/MSRV gates against the current main merge base