fix(engine): restore default blend on NaN/negative calibration weights

[joaovictor91123]

Summary

• Align gate-verdict, reviewer-consensus, and finding-severity normalizeCompositeWeights with pairwise-calibration.ts: NaN/negative weights fall back to each file's documented default blend instead of collapsing to a 100%-objective-anchor composite.
• Keep explicit all-zero weights returning real zeros so existing objective-only fallback tests stay valid.
• Add an invalid-weight unit test in each of the three suites (mirroring pairwise-calibration.test.ts).

Closes #8643

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:

• Skipped monorepo-wide UI/MCP/workers/actionlint/audit checks: this PR only changes packages/loopover-engine calibration composers and their unit tests. Validated with tsc + targeted node --test for the invalid-weight and explicit all-zero cases in all three suites (plus pairwise). Full codecov/patch will run in CI.

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.

UI Evidence

Not applicable - engine-only change, no visible UI.

State / title	JPG/PNG evidence
N/A

Notes

• Mirrors the isInvalidWeight() distinction already present in pairwise-calibration.ts (fix(engine): pairwise-calibration.js's normalizePairwiseWeights silently restores the default 50/50 blend on explicit all-zero weights, unlike its three sibling calibration modules (#6170 precedent) #7443).

[superagent-security]

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

[codecov]

Codecov Report

❌ Patch coverage is 66.66667% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 93.77%. Comparing base (4217721) to head (03022f1).
⚠️ Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
...oopover-engine/src/finding-severity-calibration.ts	66.66%	1 Missing and 1 partial ⚠️
...es/loopover-engine/src/gate-verdict-calibration.ts	66.66%	1 Missing and 1 partial ⚠️
...pover-engine/src/reviewer-consensus-calibration.ts	66.66%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8721      +/-   ##
==========================================
- Coverage   93.79%   93.77%   -0.02%     
==========================================
  Files         797      797              
  Lines       79477    79492      +15     
  Branches    24078    24087       +9     
==========================================
+ Hits        74542    74547       +5     
- Misses       3563     3566       +3     
- Partials     1372     1379       +7     

Flag	Coverage Δ
backend	95.04% <66.66%> (-0.02%)	⬇️

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

Files with missing lines	Coverage Δ
...oopover-engine/src/finding-severity-calibration.ts	33.33% <66.66%> (+0.73%)	⬆️
...es/loopover-engine/src/gate-verdict-calibration.ts	39.65% <66.66%> (+0.60%)	⬆️
...pover-engine/src/reviewer-consensus-calibration.ts	99.01% <66.66%> (-0.99%)	⬇️

... and 1 file with indirect coverage changes

[loopover-orb]

Caution

🛑 LoopOver review result - fixes required

_{Review updated: 2026-07-26 01:07:02 UTC}

6 files · 1 AI reviewer · no blockers · CI failing · unstable

🛑 Suggested Action - Fix Blockers

Review summary
The AI review returned non-blocking notes for this change but did not include a separate narrative summary. Review the nits below before deciding this PR.

Nits — 5 non-blocking

• The `isInvalidWeight` helper is duplicated verbatim across four files (pairwise-calibration.ts, gate-verdict-calibration.ts, reviewer-consensus-calibration.ts, finding-severity-calibration.ts); consider extracting it to a shared internal util given this is the second convergence PR to note this duplication pattern.
• reviewer-consensus-calibration.ts crosses the repo's 400-line long-file threshold per the external size-smell brief (~424 lines), though this PR only adds ~16 lines to it so the growth predates this change.
• The inline comments repeat almost identically across all three files ('NaN/negative inputs still recover to DEFAULT_COMPOSITE_WEIGHTS...'), which is fine for now but will need synchronized edits if the fallback logic changes again.
• Consider hoisting `isInvalidWeight` and `finiteNonNegative` into a small shared module imported by all four calibration files to avoid future drift between them.
• If reviewer-consensus-calibration.ts keeps growing, consider splitting the dimension-normalization/vote-summarization helpers into a separate file.

CI checks failing

• codecov/patch — 66.66% of diff hit (target 99.00%)

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	#8643
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: 161 registered-repo PR(s), 73 merged, 5 issue(s).
Contributor context	✅ Confirmed Gittensor contributor	joaovictor91123; Gittensor profile; 161 PR(s), 5 issue(s).
Improvement	✅ Minor	risk: clean · value: minor · LLM: minor

Linked issue satisfaction

Addressed
All three composer files add an isInvalidWeight check that returns DEFAULT_COMPOSITE_WEIGHTS when NaN/negative weights are present while preserving the explicit-all-zero real-zeros behavior, and each file gains a mirrored invalid-weight test asserting the 45/35/20 default (not objective-only collapse).

Review context

• Author: joaovictor91123
• Role context: outside_contributor
• Public audience mode: oss maintainer
• Lane context: Repository is configured for direct PR review.
• Public profile languages: Python, JavaScript, MDX, TypeScript, C++, CSS, Rust
• Official Gittensor activity: 161 PR(s), 5 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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[loopover-orb]

LoopOver is closing this pull request on the maintainer's behalf (CI is failing (codecov/patch)). This is an automated maintenance action — to pursue this change, please open a new pull request with the issues resolved. Closed PRs may be analyzed later to improve review accuracy, but they are not automatically reopened or re-reviewed.