docs(g2): S2a decision — retire the X5-scale load benchmark

[brownjuly2003-code]

What

S2a of the G2 closeout plan: the binding decision on the fate of the "45.8M rows" load/benchmark subsystem, written as a mechanical execution spec for S2b (full X5 removal).

Decision: retire the at-scale benchmark as historical; keep the infrastructure/dv2/load-test/ harness alive and gating at synthetic kitchen-seed scale; build no bulk generator.

• Rationale: legend-fit (generator-spec pins demo value away from order volume; ~2,800 orders/day makes 45.8M line items absurd), no CI/runbook consumer (the DV2 bench is a manual Mac-only kind-cluster job; CI's load-test.yml is the unrelated API-tier gate), honesty (numbers become unreproducible once the dataset is gone), cost (a Mac-only multi-day generator to keep one headline).
• Contains: file-disposition table for every load-test/benchmark path from the audit, ready-made replacement text for run-bench.sh/job.yaml/READMEs, a full ready-made rewrite of docs/dv2-multi-branch/load-test-baseline.md, and two dependency discoveries the audit's file list missed (test_dv2_postgres_ingestion.py is the only PostgresVaultWriter coverage and imports the x5 package; test_dv2_supplier_reference.py pins hash equality against x5 mappers).
• Docs-only; no code touched. This is a process document — S2b deletes it in its final commit so the S8 grep -ri x5 gate passes.

Verification

• Read at 63a585f: load-test infra, baseline doc, x5 loader package, dbt/spec/domain/schema/demo-evidence references, CI workflows, importers of the x5 package and pg_vault_writer.
• Verified docs/benchmark*.md, queries/*.sql, apply.sh, dataflow.html are already X5-free (dispositioned as no-action).

🤖 Generated with Claude Code

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