feat: FMA actuation path classification, hit rates, and per-path timing

[rubambiza]

Summary

• Replace pod-name heuristic for actuation path classification with timestamp-based logic (launcher creationTimestamp vs requester creationTimestamp)
• Rename T_LUKE_WARM to T_COLD_LAUNCHER to align with updated FMA terminology
• Add Hot_hit_rate, Warm_hit_rate, cold_launcher_rate per iteration
• Add upper-bound per-path timing: T_wake (hot), T_instance_create (warm), T_cold_launcher (cold)

Test plan

• Run FMA scenario with hot-start config and verify T_hot classification + t_wake populated
• Run FMA scenario with warm-start config and verify T_warm classification + t_instance_create populated
• Run FMA scenario with cold-start config (no pre-existing launcher) and verify T_cold_launcher classification + t_cold_launcher populated
• Verify hit rates sum to 1.0 per iteration
• Verify JSON output includes new fields without breaking existing consumers

Related

• Closes [Feature]: FMA actuation path classification, hit rates, and per-path timing (Phases 1-2) #1422
• Will leverage Log call durations on launcher/instance/K8s actuation calls llm-d-incubation/llm-d-fast-model-actuation#522 (DPC call duration logging) in a follow-up PR for tighter timing measurements
• Benchmarking doc: docs: Address PR #381 review feedback llm-d-incubation/llm-d-fast-model-actuation#454