fix(sdk): retry failed alerts from the same ledger

[svllvsx]

Summary

• Keep the cursor at or before a failed alert's ledger, even when an earlier action in that ledger succeeded or was a skipped accept.
• Add two-run regressions sharing the same store, plus successful same-ledger batches and different-ledger failure coverage.
• Preserve the numeric cursor format. Replaying a failed ledger can repeat an earlier successful alert; the documentation now makes that trade-off explicit.

Test plan

• pnpm lint && pnpm typecheck && pnpm test pass locally (1,896 tests on current main).
• pnpm format:check, pnpm typecheck:api, and pnpm coverage pass.
• All 17 alert-keeper tests pass. Both new same-ledger regression cases fail against the original code and pass with the fix.

Closes #1060

[vercel]

@svllvsx is attempting to deploy a commit to the Collins' projects Team on Vercel.

A member of the Team first needs to authorize it.

[drips-wave]

@svllvsx Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits.

You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀

Learn more about application limits

[collinsezedike]

@svllvsx thank you for the contribution. There are more open issues if you would like to keep going.