fix(queue-trends): return null review velocity when observedDays is zero

[andriypolanski]

Summary

• Documents the baseline-selection invariant in buildWindow: once a baseline is found (fetchedAt <= latest - windowDays), observedDays is always at least the requested window span, so ready windows divide safely.
• Adds regression tests that duplicate latest fetchedAt timestamps still yield finite reviewVelocityPerDay and that ready windows always have observedDays >= windowDays.
• Does not add a null/zero-day velocity branch — that path is unreachable for ready windows given how baseline is chosen (lines 88–90).

Why not null on zero observedDays?

The gate flagged the prior approach as a dead fix: baseline must be at or before targetMs, so observedDays <= 0 cannot occur on any ready buildWindow result. A null-velocity guard would never run on the real path and contradicted the PR title.

Scope

• The PR title follows type(scope): short summary Conventional Commit format.
• Focused change in src/services/queue-trends.ts + tests only.

Validation

• npm run test:ci green
• npm run test:coverage green

Test plan

• test/unit/queue-trends.test.ts — duplicate latest fetchedAt → no Infinity; ready windows → observedDays >= windowDays and finite velocity.

Files changed

File	Change
src/services/queue-trends.ts	Invariant comment only (no dead null branch)
test/unit/queue-trends.test.ts	Regression + invariant tests

PR body note (important)

Update the open PR title and description to match this summary. Remove any claim about “return null when observedDays is zero” — that was incorrect for the ready-window path.

[loopover-orb]

Warning

🟨🟨🟨🟨🟨🟨🟨🟨🟨🟨🟨🟨

⏸️ Gittensory review result - manual review recommended

_{Review updated: 2026-06-30 07:52:52 UTC}

2 files · 1 AI reviewer · no blockers · readiness 71/100 · CI green · unknown

⏸️ Suggested Action - Manual Review

• Touches a guarded path — held for manual review

Review summary
This change documents the real buildWindow invariant and adds tests around duplicate latest timestamps plus ready-window observedDays bounds. The production change is safe because the baseline selection requires fetchedAt <= latest - windowDays before computing observedDays, so ready windows cannot divide by zero. The notable issue is metadata drift: the PR title still claims a null-on-zero behavior that the code intentionally does not implement.

Nits — 4 non-blocking

• nit: Pull request metadata should be updated because the current title says `return null review velocity when observedDays is zero`, while `src/services/queue-trends.ts:90` intentionally keeps finite velocity for ready windows.
• Update the PR title to match the implemented invariant/test-only fix, for example `test(queue-trends): cover ready-window observedDays invariant` or `docs(queue-trends): document ready-window observedDays invariant`.
• Readiness score is below the configured threshold — Use the readiness panel as advisory maintainer context; the score does not block this PR.
• Touches a guarded path — held for manual review — A maintainer must review and merge this change.

Signal	Result	Evidence
Code review	✅ No blockers	1 reviewer
Linked issue	⚠️ Missing	No linked issue or no-issue rationale found.
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 (size label size:XS; no linked issue context).
Validation posture	❌ 5/25	Preflight is holding this PR; address the blocker before review.
Contributor workload	✅ 10/10	Author activity: 87 registered-repo PR(s), 60 merged, 5 issue(s).
Contributor context	✅ Confirmed Gittensor contributor	andriypolanski; Gittensor profile; 87 PR(s), 5 issue(s).
Gate result	⚠️ Not blocking	Advisory; not blocking this PR.

Review context

• Author: andriypolanski
• Role context: outside_contributor
• Public audience mode: oss maintainer
• Lane context: Repository registration is not available in the local Gittensory cache.
• Public profile languages: not available
• Official Gittensor activity: 87 PR(s), 5 issue(s).
• PR-specific overlap: none found.

Contributor next steps

• Explain no-issue PR.
• Fix the blocker.
• Refresh registry data or choose a registered active repo.
• Link the issue being solved, or explicitly explain why this is a no-issue PR.

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.

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

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