feat(engine): aggregate REGRESSED-verdict track-record statistics from persisted backtest CI results

[cleanjunc]

Summary

Closes #8140.

Adds the aggregation #8105's Phase-2 merge-gating decision needs: computeRegressedVerdictTrackRecord (packages/loopover-engine/src/calibration/backtest-track-record.ts) — a pure function turning an array of historical BacktestComparison results (#8086) into the decision summary (total runs, REGRESSED count, a regressedRate that stays null for zero runs — the module's established never-coerce-unknown-to-0 discipline — and a per-ruleId Map breakdown of total/regressed/improved/unchanged), plus the thin CLI (scripts/backtest-track-record.ts) that reads the rows the advisory backtest CI check persists (#8138, calibration.threshold_backtest_run in audit_events, metadata.comparison) and prints the summary.

• The event-type literal mirrors THRESHOLD_BACKTEST_EVENT_TYPE in src/services/threshold-backtest-run.ts with a keep-in-sync comment — that module is Worker-bound (D1 repository import graph) and deliberately not imported into a standalone script, the same posture the merged backtest-corpus-export.ts takes toward signal-tracking-wire's private helpers.
• The CLI mirrors export-d1-data.ts's parseArgs/d1Query shell-out exactly (read-only, fail-loud) and contains no logic beyond the read, the JSON-parse (fail-open per-row, matching listAuditEventsByType's own posture), the pure-function call, and printing — per the epic's established pure-core/thin-IO exemption, no dedicated wrapper test.
• Barrel export added after the backtest-report.js line, continuing the module's export order.

Scope

• The PR title follows type(scope): short summary Conventional Commit format, for example fix(api): restore profile access checks.
• This PR is focused and does not mix unrelated backend, UI, MCP, docs, dependency, and deploy changes.
• This follows CONTRIBUTING.md and does not reintroduce GitHub Pages, VitePress, site/, or CNAME.
• I linked a currently open issue this PR resolves (e.g. Closes #123) — a linked open issue is required for every contributor PR.

Validation

• git diff --check
• npm run actionlint
• npm run typecheck
• npm run test:coverage locally; codecov/patch requires ≥99% coverage of the lines AND branches you changed (aim for 100% on your diff so CI variance does not fail near the threshold). Global coverage is a non-blocking trend with a loose 90% backstop, not the gate.
• npm run test:workers
• npm run build:mcp
• npm run test:mcp-pack
• npm run ui:openapi:check
• npm run ui:lint
• npm run ui:typecheck
• npm run ui:build
• npm audit --audit-level=moderate
• New or changed behavior has unit/integration tests for new branches, fallback paths, and sanitizer boundaries

If any required check was skipped, explain why:

• Ran the directly-affected gates: npm run build --workspace @loopover/engine (green), the engine node --test on the mandated new test file (4/4 — zero runs → null rate, all-clean, some-regressed, multi-rule breakdown, exactly the issue's enumerated cases) and the root-side vitest coverage twin (4/4, direct engine-src import — the pattern this module's merged calibration: pure BacktestCase corpus builder from RuleFiredEvent/HumanOverrideEvent pairs #8083/calibration: Pareto-floor comparator between two BacktestScoreReports #8086/calibration: render a backtest score/comparison report as Markdown #8088 twins established so the new file's coverage is visible to codecov/patch), plus the CLI's usage-guard smoke. Real CI re-runs typecheck and the sharded suite here.
• workers/mcp/ui/audit/actionlint: untouched surfaces — one engine module + barrel line, one CLI script, two test files; zero dependency changes.

Safety

• No secrets, wallet details, hotkeys, coldkeys, user PATs, private keys, raw trust scores, private rankings, or private maintainer evidence are exposed.
• Public GitHub text stays sanitized, low-noise, and does not imply compensation guarantees or optimization tactics.
• Auth, cookie, CORS, GitHub App, Cloudflare, or session changes include negative-path tests.
• API/OpenAPI/MCP behavior is updated and tested where needed.
• UI changes use live API data or real empty/error/loading states, not production mock/demo fallbacks.
• Visible UI changes include a UI Evidence section below with JPG/JPEG or PNG screenshots arranged as organized, captioned, clickable thumbnails. SVG screenshots are not used as review evidence. Review-only screenshots or recordings are not committed to the repository.
• Public docs/changelogs are updated where needed; changelogs are only edited for release-prep PRs.

The three unchecked Safety boxes are N/A: no auth/session/UI change — a pure engine module + read-only CLI.

UI Evidence

N/A — no UI change.

Notes

• Once Scaffold the advisory backtest CI workflow + threshold-only comparison, and persist each run's result #8138's check has accumulated real runs, tsx scripts/backtest-track-record.ts --db <db> --remote gives the maintainer the one-command summary Decide + implement whether a REGRESSED backtest verdict should ever gate a merge (Phase 2) #8105 asks for, instead of reading individual PR comments.

[superagent-security]

Superagent didn't find any vulnerabilities or security issues in this PR.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.03%. Comparing base (9258836) to head (d8b3dc6).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #8143   +/-   ##
=======================================
  Coverage   92.03%   92.03%           
=======================================
  Files         763      764    +1     
  Lines       77506    77520   +14     
  Branches    23425    23430    +5     
=======================================
+ Hits        71332    71346   +14     
  Misses       5062     5062           
  Partials     1112     1112           

Flag	Coverage Δ
shard-1	57.65% <100.00%> (+3.95%)	⬆️
shard-2	50.89% <0.00%> (-3.84%)	⬇️
shard-3	54.47% <0.00%> (+0.36%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...er-engine/src/calibration/backtest-track-record.ts	100.00% <100.00%> (ø)

[loopover-orb]

Tip

✅ LoopOver review result - approve/merge recommended

_{Review updated: 2026-07-23 03:33:17 UTC}

5 files · 1 AI reviewer · no blockers · readiness 100/100 · CI green · clean

✅ Suggested Action - Approve/Merge

• safe to merge

Review summary
This PR adds a pure aggregation function `computeRegressedVerdictTrackRecord` that folds an array of `BacktestComparison` results into total/regressed counts, a null-safe `regressedRate`, and a per-ruleId breakdown, plus a thin read-only CLI (`scripts/backtest-track-record.ts`) that pulls persisted rows from `audit_events` via `wrangler d1 execute` and prints the summary. The aggregation logic is straightforward and correctly exhaustive over the three verdict states, the zero-runs null-rate case is explicitly tested, and the barrel export is added in the right place. The CLI's SQL interpolates only a hardcoded constant (not user input) so there's no injection risk, and the fail-open per-row JSON parse mirrors the existing `listAuditEventsByType` posture as claimed.

Nits — 5 non-blocking

• scripts/backtest-track-record.ts:36 hardcodes the 256*1024*1024 maxBuffer and other magic numbers (500-char stderr slice) without a named constant — minor, matches export-d1-data.ts's existing style per the PR description but worth a quick check for consistency.
• packages/loopover-engine/src/calibration/backtest-track-record.ts has no branch test for a comparison with an unrecognized/malformed ruleId feeding into the CLI's `typeof comparison.ruleId === 'string'` guard — worth a one-line CLI-level sanity test even under the pure-core/thin-IO exemption.
• The CLI's `d1Query` error message truncates stderr/stdout to 500 chars — reasonable, but consider noting in a comment why 500 was chosen if it's arbitrary.
• Consider extracting the `256 * 1024 * 1024` maxBuffer literal in scripts/backtest-track-record.ts:36 into a named constant like export-d1-data.ts likely already does, for consistency.
• The per-rule Map iteration order in the CLI's print loop (scripts/backtest-track-record.ts:69) is insertion order — fine for now, but if stable alphabetical output is ever needed for snapshotting CI comments, sort ruleIds first.

Decision drivers

• ✅ Code review — No blockers (1 reviewer)
• ✅ Gate result — Passing (No configured blocker found.)

Context & advisory signals — never blocks the verdict

Signal	Result	Evidence
Linked issue	✅ Linked	#8140
Related work	✅ No active overlap found	No same-issue or scoped active PR overlap found.
Change scope	✅ 20/20	Low review scope from cached public metadata (1 linked issue).
Validation posture	✅ 25/25	PR body includes validation/test evidence.
Contributor workload	✅ 10/10	Author activity: 52 registered-repo PR(s), 18 merged, 33 issue(s).
Contributor context	✅ Confirmed Gittensor contributor	cleanjunc; Gittensor profile; 52 PR(s), 33 issue(s).
Improvement	✅ Minor	risk: clean · value: minor · LLM: moderate

Linked issue satisfaction

Addressed
The PR adds the pure computeRegressedVerdictTrackRecord function in packages/loopover-engine/src/calibration/ with the requested total/regressed rate and per-ruleId Map breakdown, includes tests covering zero runs, all-clean, some-regressed, and multi-ruleId cases, and adds a thin CLI wrapper that reads audit_events rows and prints the summary.

Review context

• Author: cleanjunc
• Role context: outside_contributor
• Public audience mode: oss maintainer
• Lane context: Repository is configured for direct PR review.
• Public profile languages: Python, TypeScript, JavaScript, Scala
• Official Gittensor activity: 52 PR(s), 33 issue(s).
• PR-specific overlap: none found.

Contributor next steps

• Keep the PR focused and include validation evidence before maintainer review.

Signal definitions

• Related work = same linked issue, overlapping active PRs, or title/path similarity.
• Change scope = cached public metadata such as size labels, draft state, and review-burden hints.
• Validation posture = whether the PR provides enough public validation/test evidence for maintainer review.
• Contributor workload = public contributor activity and cleanup pressure, not a repo-wide quality failure.
• Contributor context = public GitHub/Gittensor identity context; non-Gittensor status is not a blocker.

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_{🟩 Safe / merged · 🟦 Advisory · 🟨 Held for review · 🟥 Blocked / closed}

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