feat(bench): RFC 0031 L4 harness — aggregation pair, matrix parser, param picker

[jensholdgaard]

What

The L4 harness fixture-level slice for RFC 0031 — RFC0031.5 un-stubbed. Base: rfc0002-l4-green-execution (in review as #533 — this PR is stacked and will need a rebase once that merges).

• ourios_aggregate_answer: runs template_id == {id} | count by param({p}), bucket({w}) and decodes QueryResult.aggregate into an AggKey → count map; bytes_read is the grouped-count scan total (RFC 0002 §6.5 guarantees zero materialize/registry components on this path).
• parse_loki_matrix: decodes Loki/Prometheus resultType: "matrix" responses into the same AggKey shape. Bucket alignment documented: count_over_time(range[w]) at eval instant t covers (t-w, t], so evaluating at t = (k+1)·w yields the Ourios-equivalent bucket [k·w, (k+1)·w).
• pick_frequency_pair: a fourth corpus pass (mirrors pick_template_pair) choosing (template_id, param_position, bucket_width) where distinct group values fall in 2..=50 and rows ≥ 4 — rejecting both single-value and kafka-style per-line-unique slots. Every rejection is a loud eprintln!, no silent fallthrough.
• PairClass::L4 added with GateKind::MustWin; frozen_gate_failures explicitly skips it and the report prints both byte channels labeled "§7 DEFERRED — reported only" — M_L4 stays unfrozen until a real dispatch measures it.

⚠️ Known gap — NOT live-wired into the dispatch loop yet

This slice proves the machinery at the fixture level (a hand-built synthetic Loki matrix response, no container). PairClass::L4 is not yet built into class_pair_specs/the live measurement loop in rfc0031_indicative_comparative_run — a dispatch today still won't touch L4. That wiring is the next slice; flagging it here so nothing assumes L4 is measurable yet.

Checks run

cargo fmt --all --check; workspace cargo clippy --all-targets --all-features -- -D warnings; strict rustdoc on ourios-bench; cargo nextest run -p ourios-bench — 165 passed, 7 skipped (all pre-existing container/dispatch-only ignores). New dep: chrono (already transitively pinned via ourios-querier) added directly for RFC 3339 bucket-key decoding.

🤖 Generated with Claude Code

https://claude.ai/code/session_01WQY9wfrfRggqSpMLH8Xj3Y

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📥 Commits

Reviewing files that changed from the base of the PR and between 2b46313 and be74f30.

⛔ Files ignored due to path filters (1)

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📒 Files selected for processing (4)

• crates/ourios-bench/Cargo.toml
• crates/ourios-bench/src/comparative.rs
• crates/ourios-bench/src/lib.rs
• crates/ourios-bench/tests/rfc0031_comparative.rs

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• Create PR with unit tests
• Commit unit tests in branch rfc0031-l4-harness

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[Copilot]

Pull request overview

This PR un-stubs the RFC 0031 L4 (frequency aggregation) comparative harness slice in ourios-bench, adding machinery to (1) execute Ourios count by param(n), bucket(w) queries, (2) parse Loki/Prometheus resultType: "matrix" responses into the same grouped-count shape, and (3) pick a fixture-derived L4 (template_id, param, bucket_width) candidate for deterministic equivalence checks.

Changes:

• Add OuriosAggregateAnswer + ourios_aggregate_answer and Loki matrix parsing (parse_loki_matrix) for L4 grouped-count equivalence.
• Add L4 pair picker utilities (pick_frequency_pair, pick_bucket_width, regex capture construction) and a new RFC0031.5 fixture-level test.
• Wire PairClass::L4 into the harness’ reporting/gating shape (explicitly deferred for frozen-gate evaluation).

Reviewed changes

Copilot reviewed 4 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
crates/ourios-bench/tests/rfc0031_comparative.rs	Adds RFC0031.5 L4 fixture test, L4 pair picking utilities, and integrates PairClass::L4 into reporting/skip logic.
crates/ourios-bench/src/lib.rs	Re-exports new L4 comparative helpers/types from comparative.
crates/ourios-bench/src/comparative.rs	Implements Ourios aggregation extraction (ourios_aggregate_answer) and Loki matrix parsing (parse_loki_matrix) + associated tests.
crates/ourios-bench/Cargo.toml	Adds a direct chrono dependency for RFC3339 bucket-key decoding.
Cargo.lock	Records the new chrono dependency for ourios-bench.

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Copilot reviewed 4 out of 5 changed files in this pull request and generated 1 comment.

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Pull request overview

Copilot reviewed 4 out of 5 changed files in this pull request and generated 1 comment.

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Pull request overview

Copilot reviewed 4 out of 5 changed files in this pull request and generated no new comments.