fix(ui): guard leading tab and CR in escapeCsvCell against formula injection

[jaytbarimbao-collab]

Summary

escapeCsvCell (apps/loopover-ui/src/lib/csv-export.ts) guards spreadsheet formula-injection by prefixing ' when a value starts with =, +, -, or @. But a leading TAB (\t) or CR (\r) is also a formula-injection vector: a spreadsheet strips the leading whitespace and still evaluates the =/+/-/@ formula that follows, so a telemetry-sourced value like "\t=HYPERLINK(\"evil\")" slipped past the guard unescaped.

Fix

Extend the guard regex from /^[=+\-@]/ to /^[=+\-@\t\r]/, so a leading tab or CR is guarded the same way. No other behavior changes — RFC-4180 quoting is unchanged (a \r value still additionally quotes as before).

Verification

csv-export.test.ts gains a #7439 case asserting "\t=1+1" → "'\t=1+1", "\t@SUM(A1)" → "'\t@SUM(A1)", "\r=1+1" → quoted-and-guarded, and that a plain value is untouched. All 7 csv-export tests pass.

Closes #7439

[superagent-security]

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

[loopover-orb]

Tip

✅ LoopOver review result - approve/merge recommended

_{Review updated: 2026-07-20 13:56:43 UTC}

2 files · 1 AI reviewer · no blockers · readiness 98/100 · CI green · clean

✅ Suggested Action - Approve/Merge

• safe to merge

Review summary
This is a small, correct security hardening fix: it extends the formula-injection guard regex in escapeCsvCell to also cover leading TAB and CR characters, closing a real gap where a spreadsheet strips leading whitespace before evaluating a formula. The test additions directly exercise the new behavior (tab-prefixed formulas, CR-prefixed formula with quoting interaction, and an unchanged plain-value case), and the RFC-4180 quoting logic downstream is untouched and still correct since \r triggers the pre-existing needsQuotes check. The fix is applied at the correct layer (the single shared escapeCsvCell function used by toCsv) rather than patched at call sites.

Nits — 4 non-blocking

• The verification claims 'All 7 csv-export tests pass' but the file shows 7 `it(...)` blocks across two `describe` blocks — worth double-checking the count language in the PR description is accurate, though this doesn't affect the code itself.
• The inline comment in csv-export.ts (lines 3-5) is a bit long for what is a one-line regex change; could be tightened to a single line referencing fix(ui): CSV export formula-injection guard doesn't cover leading tab/CR, only =+-@ #7439.
• Consider also guarding leading '|' (pipe) since some spreadsheet DDE-exploits use it as a fourth formula-trigger character in certain locales, though this is out of scope for this issue-linked fix.
• The new test case's naming and structure match the existing 'guards formula-injection prefixes' test well — good consistency with existing conventions in apps/loopover-ui/src/lib/csv-export.test.ts.

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	#7439
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: 175 registered-repo PR(s), 85 merged, 14 issue(s).
Contributor context	✅ Confirmed Gittensor contributor	jaytbarimbao-collab; Gittensor profile; 175 PR(s), 14 issue(s).
Improvement	✅ Minor	risk: clean · value: minor

Review context

• Author: jaytbarimbao-collab
• Role context: outside_contributor
• Public audience mode: oss maintainer
• Lane context: Repository is configured for direct PR review.
• Public profile languages: Rust
• Official Gittensor activity: 175 PR(s), 14 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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