test(perf): count repository work in registry benchmarks

[ricardo-devis-agullo]

Summary

• instrument benchmark storage operations and normalized paths, including reset-safe concurrency metrics
• run the cold-burst harness through the real repository and gate manifest/artifact work counts
• persist raw and per-request server benchmark work, with compatible baseline, result verification, success, and regression CLI gates
• add synthetic positive/negative assertion coverage and register the burst benchmark command

Test plan

• npm --workspace packages/oc run build
• npm --workspace packages/oc run test-silent (1005 passing)
• npx mocha --timeout 20000 packages/oc/test/unit/tasks-benchmark-assertions.js
• npm --workspace packages/oc run bench:burst
• storage-simulated benchmark, 2 repetitions, 100% success
• batch-storage benchmark, 2 repetitions, 100% success
• explicit same-machine baseline comparison self-check
• Mend generated-code security scans

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