fix(miner): prime runLoop's ledger cursor with an indexed MAX(seq) lookup

[bitfathers94]

fix(miner): prime runLoop's ledger cursor with an indexed MAX(seq) lookup

Add EventLedger.latestSeq(), backed by a COALESCE(MAX(seq), 0) statement prepared at
open time, and have runLoop read it instead of loading and JSON-parsing every row in
the ledger just to take the last one's seq.

Closes #10008

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✅ LoopOver review result - approve/merge recommended

_{Review updated: 2026-07-31 14:52:02 UTC}

5 files · 1 AI reviewer · no blockers · readiness 95/100 · CI green · clean

✅ Suggested Action - Approve/Merge

• safe to merge

Review summary
This PR replaces runLoop's O(n) `readEvents({}).at(-1)?.seq` cursor priming with a new `latestSeq()` method backed by a dedicated `COALESCE(MAX(seq), 0)` prepared statement, avoiding a full table scan and JSON.parse of every row just to get the last seq. The change is correct: `latestSeq()` mirrors the existing `nextSeqStatement` pattern, is properly wired through the EventLedger interface, default-singleton export, and all mock/stub call sites in the test suite (miner-mcp-contract.test.ts, miner-loop-cli.test.ts). Tests cover the new method directly (empty ledger, after appends, singleton helper) and pin the regression via a spy that asserts `readEvents` is never called during cursor priming.

Nits — 4 non-blocking

• nit: event-ledger.ts's `latestSeqStatement` and `nextSeqStatement` both scan the same MAX(seq) — consider whether a covering index note is worth adding since seq is UNIQUE (likely already indexed), though this is a micro-perf point given SQLite already indexes UNIQUE columns.
• nit: the new `latestSeq()` on the EventLedger type isn't documented with a one-line comment describing its distinction from `nextSeq` (used internally for appends) versus this public read-only cursor value, though the inline comment above the implementation covers this adequately.
• loop-cli.ts:342 — the fix is correctly scoped to the exact line flagged in issue miner(loop): runLoop reads and JSON-parses the entire event ledger to obtain one seq number #10008; no further changes needed there.
• event-ledger.ts:238-241 — consider whether `latestSeq()` and the internal `nextSeqStatement` could share one prepared statement (nextSeq - 1) to avoid maintaining two near-identical SQL strings, though this is a minor DRY nit not worth blocking on.

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	#10008
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	⚠️ 20/25	Preflight is ready, but the PR body does not name the validation run.
Contributor workload	✅ 10/10	Author activity: 140 registered-repo PR(s), 99 merged, 3 issue(s).
Contributor context	✅ Confirmed Gittensor contributor	bitfathers94; Gittensor profile; 140 PR(s), 3 issue(s).
Improvement	✅ Minor	risk: clean · value: minor · LLM: moderate

Linked issue satisfaction

Addressed
The PR adds EventLedger.latestSeq() backed by a COALESCE(MAX(seq),0) statement prepared at open time next to nextSeqStatement, exposes it on the EventLedger type and as a module-level export, updates runLoop to use it instead of readEvents({}), and updates all injected test doubles (loop-cli, mcp-contract tests) plus adds dedicated unit tests verifying 0-on-empty and equality with the appended seq

Review context

• Author: bitfathers94
• Role context: outside_contributor
• Public audience mode: oss maintainer
• Lane context: Repository is configured for direct PR review.
• Public profile languages: TypeScript
• Official Gittensor activity: 140 PR(s), 3 issue(s).
• PR-specific overlap: none found.

Contributor next steps

• Start here: Add validation command/output.

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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[superagent-security]

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

[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 80.71%. Comparing base (e3f7b45) to head (01ebc1b).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #10259      +/-   ##
==========================================
+ Coverage   80.60%   80.71%   +0.10%     
==========================================
  Files         283      285       +2     
  Lines       59101    59434     +333     
  Branches     7000     7105     +105     
==========================================
+ Hits        47641    47974     +333     
  Misses      11167    11167              
  Partials      293      293              

Flag	Coverage Δ
backend	100.00% <100.00%> (?)

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

Files with missing lines	Coverage Δ
packages/loopover-miner/lib/event-ledger.ts	100.00% <100.00%> (ø)
packages/loopover-miner/lib/loop-cli.ts	100.00% <100.00%> (ø)

[loopover-orb]

LoopOver approves — the gate is satisfied and CI is green.