fix(review): bound fetchShotContentBlock's screenshot fetch with a timeout

[shin-core]

What

fetchShotContentBlock (src/review/visual/capture.ts) fetched a screenshot URL with a bare fetch(url) and no time bound. Every other external fetch in this file and its siblings is timeout-bounded — including resolveShotUrl in this same file, which already uses AbortSignal.timeout(EXTERNAL_SCREENSHOT_FETCH_TIMEOUT_MS) (8s). A slow or hanging shot host (a self-host operator's storage backend, an R2/S3 proxy) could stall the review pipeline for that PR indefinitely.

How

Pass the same AbortSignal.timeout(EXTERNAL_SCREENSHOT_FETCH_TIMEOUT_MS) to the fetch, reusing the constant already declared in this file. The function's existing catch already returns undefined on any rejection, so a TimeoutError is handled with no other change.

Validation

Test added to the existing fetchShotContentBlock describe block in test/unit/visual-capture.test.ts: the fetch is called with an AbortSignal. Confirmed it fails against the unfixed code (signal is undefined) and passes with the fix. typecheck clean; the full visual-capture suite (118 tests) passes.

Closes #7070

[superagent-security]

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[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 93.75%. Comparing base (05e7af4) to head (ead6fdd).
⚠️ Report is 7 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7098      +/-   ##
==========================================
- Coverage   95.98%   93.75%   -2.23%     
==========================================
  Files         609      692      +83     
  Lines       48144    68808   +20664     
  Branches    15133    18781    +3648     
==========================================
+ Hits        46209    64511   +18302     
- Misses       1118     3302    +2184     
- Partials      817      995     +178     

Flag	Coverage Δ
shard-1	43.34% <0.00%> (ø)
shard-2	36.89% <0.00%> (ø)
shard-3	33.16% <100.00%> (ø)
shard-4	34.39% <100.00%> (ø)
shard-5	31.67% <0.00%> (-0.01%)	⬇️
shard-6	46.07% <0.00%> (ø)

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

Files with missing lines	Coverage Δ
src/review/visual/capture.ts	94.90% <100.00%> (ø)

... and 83 files with indirect coverage changes

[loopover-orb]

Warning

⏸️ LoopOver review result - manual review recommended

_{Review updated: 2026-07-17 21:21:48 UTC}

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

⏸️ Suggested Action - Manual Review

Review summary
Small, targeted fix that adds the existing EXTERNAL_SCREENSHOT_FETCH_TIMEOUT_MS AbortSignal.timeout to fetchShotContentBlock's fetch call, mirroring resolveShotUrl in the same file. The existing catch already treats any rejection (including TimeoutError) as undefined, so no other behavior changes, and a test verifies the signal is passed. This closes issue #7070 as described and is a correct, minimal, well-scoped change.

Nits — 4 non-blocking

• The added comment in capture.ts is a bit verbose for a one-line change; a shorter inline note would suffice.
• The test only asserts that a signal is passed, not that it's specifically an AbortSignal.timeout with the correct duration — consider asserting on the constant value too.
• src/review/visual/capture.ts: consider extracting the fetch+timeout pattern into a small helper if a third call site needing this timeout appears, to avoid repeating the AbortSignal.timeout(...) call.
• test/unit/visual-capture.test.ts: could assert the timeout duration matches EXTERNAL_SCREENSHOT_FETCH_TIMEOUT_MS for stronger coverage.

Flagged checks (non-blocking)

• Contributor trust — Contributor flagged for review

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	#7070
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: 61 registered-repo PR(s), 37 merged, 0 issue(s).
Contributor context	✅ Confirmed Gittensor contributor	shin-core; Gittensor profile; 61 PR(s), 0 issue(s).
Improvement	✅ Minor	risk: clean · value: minor

Review context

• Author: shin-core
• Role context: outside_contributor
• Public audience mode: oss maintainer
• Lane context: Repository is configured for direct PR review.
• Public profile languages: not available
• Official Gittensor activity: 61 PR(s), 0 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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