fix(content-lane): harden duplicates block-scalar header detection

[joaovictor91123]

Summary

• Harden block-scalar header detection in src/review/content-lane/duplicates.ts to match the grammar already used in source-evidence.ts (stripYamlComment, BLOCK_SCALAR_INDICATOR, isBlockScalarHeader).
• Replace the old /^[|>][+-]?\d*$/ checks in parseSimpleFrontmatter and findDuplicateFrontmatterKeys so chomping/indent permutations (|2-, >2+, etc.) and trailing inline comments (| # note) are recognized.
• Add regression tests mirroring content-lane-source-evidence.test.ts.

Closes #9290

Scope

• True leaf path: only duplicates.ts + content-lane-duplicates.test.ts (scoped CI should stay ~1 test file, same shape as merged fix(signals): render discouragedPaths in onboarding-pack preview markdown #9336 / test(signals): cover buildReviewRiskExplanation's 5-way branch logic (#9287) #9338).
• Duplicate gate: no other open PR for review/content-lane: duplicates.ts's block-scalar detection lags source-evidence.ts's hardened version (comment-tolerance, digit order) #9290; issue still open.
• Avoids hub files (processors.ts, advisory.ts) that fan out to thousands of tests and hit maintainer fix: close the remaining 5 pre-existing test failures on main #9285 flake.

Validation

• Block-scalar header permutations + comment-tolerant cases covered in unit tests.
• Full CI — expecting narrow --changed selection (not the fix: close the remaining 5 pre-existing test failures on main #9285 selfhost-pg-retention / salvageability slice).

[superagent-security]

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

[codecov]

❌ 1 Tests Failed:

Tests completed	Failed	Passed	Skipped
88	1	87	0

View the top 1 failed test(s) by shortest run time

test/unit/content-lane-duplicates.test.ts > parseSimpleFrontmatter > recognizes block-scalar headers with chomping/indent in either order and trailing comments (#9290)

Stack Traces | 0.0115s run time

AssertionError: expected 'line one line two' to be 'line one\nline two' // Object.is equality

- Expected
+ Received

- line one
- line two
+ line one line two

 ❯ test/unit/content-lane-duplicates.test.ts:67:29

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[loopover-orb]

Caution

🛑 LoopOver review result - fixes required

_{Review updated: 2026-07-27 14:19:19 UTC}

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

🛑 Suggested Action - Fix Blockers

Review summary
This PR extracts a shared `isBlockScalarHeader`/`stripYamlComment`/`BLOCK_SCALAR_INDICATOR` helper in duplicates.ts and swaps the old `/^[|>][+-]?\d*$/` check for it in both `parseSimpleFrontmatter` and `findDuplicateFrontmatterKeys`, mirroring the existing pattern in source-evidence.ts. The new regex `^[|>](?:[+-]?\d?|\d[+-]?)$` correctly accepts both chomping-then-indent and indent-then-chomping orders (`|2-`, `|-2`), and comment-stripping is applied before the test so `| # note` style headers are recognized — I traced both call sites and the logic is sound. Tests exercise all 12 indicator permutations plus three comment-trailing cases for both functions, which is solid regression coverage for a narrow, well-scoped fix tied to #9290.

Nits — 4 non-blocking

• src/review/content-lane/duplicates.ts:56-59 — `unquoteYamlScalar` still inlines its own `.replace(/\s+#.*$/, "").trim()` instead of calling the new `stripYamlComment` helper, so the comment-stripping regex is now duplicated in two places; consider having `unquoteYamlScalar` call `stripYamlComment` directly.
• The two FAILED checks (`validate`, `validate-tests`) have no detail provided, and given the branch is 1 commit behind the current default branch, that's a plausible cause worth ruling out by rebasing before assuming a defect in this diff.
• src/review/content-lane/duplicates.ts:56-59 — replace the inline comment-stripping in `unquoteYamlScalar` with a call to `stripYamlComment(trimmed)` to keep the two comment-stripping code paths from drifting apart.
• Rebase onto the latest default branch to see whether `validate`/`validate-tests` still fail, since the branch is reported 1 commit behind.

CI checks failing

• validate
• validate-tests

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	#9290
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: 130 registered-repo PR(s), 57 merged, 4 issue(s).
Contributor context	✅ Confirmed Gittensor contributor	joaovictor91123; Gittensor profile; 130 PR(s), 4 issue(s).
Improvement	✅ Minor	risk: clean · value: minor · LLM: moderate

Linked issue satisfaction

Addressed
The PR ports the exact BLOCK_SCALAR_INDICATOR/isBlockScalarHeader/stripYamlComment logic from source-evidence.ts into duplicates.ts and applies it at both call sites (parseSimpleFrontmatter and findDuplicateFrontmatterKeys), matching the requested behavior for digit-before/after-chomp and trailing-comment cases. It also adds tests in the existing duplicates.ts test file covering |2-, |- with comme

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: 130 PR(s), 4 issue(s).
• PR-specific overlap: none found.

Contributor next steps

• Start here: Triage stale or unlinked PRs.

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 is closing this pull request on the maintainer's behalf (CI is failing (validate, validate-tests)). 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.