Ledger Reconcile speed training

20/20 correct; PB 5.295s→4.856s. Reuse: fixed A/B/C/D/E slots; load openings once, scan 12 transactions once, route by first letter, skip zero deltas, emit fixed sorted strings immediately—no sort, net buckets, or second check. Slower reps added handling. Bottleneck: connector/runtime variance + 12-item scan.