ISL-174: benchmarks core e2e consolidation

[zozo123]

ISL-174: benchmarks core e2e consolidation

This is the single canonical ISL-174 PR for benchmarks.

Scope in this PR

• Add baseline CI workflow (npm ci + typecheck).
• Add validation matrix workflow with artifact upload.
• Add devops-hygiene.yml policy checks.
• Standardize environment template naming to .env.example.
• Extend benchmark result metadata (runId, requestId, startedAt).

What this brings

• Reproducible benchmark evidence with richer trace metadata.
• Better automation signal for performance/regression tracking.
• Guardrail against env-file hygiene regressions.

Follow-up policy

All additional ISL-174 benchmarks work should be appended to this same PR branch to preserve one PR per core repo.

[zozo123]

Reviewer summary

This PR upgrades benchmarks from ad-hoc runs to an auditable CI + matrix flow with run correlation metadata.

Result: performance evidence is easier to trust and compare over time.