Add Prime sandbox benchmark adapter and results

[DawgZter]

Summary

• add a Prime benchmark adapter and provider registration
• wire Prime env vars into the benchmark workflow and example env file
• reduce readiness polling latency and align the benchmark adapter's default Prime sandbox TTL to 5 minutes
• include current Prime benchmark result artifacts

Validation

• npx tsc --noEmit
• npm run bench:prime -- --iterations 10 --concurrency 10
• current results from this branch:
  • sequential: score 25.73, median 6.90s
  • staggered: score 20.54, median 7.37s
  • burst: score 23.83, median 7.04s

Dependency

• depends on Add Prime Intellect sandbox provider computesdk#428 for the first-party Prime provider package
• opening this as a draft to keep the provider-first rollout explicit