#debugging
- Chapter 6a: instrument first, find the stall
Chapter 6, part 1: workflow telemetry, and the enrichment stall where 45 stories sat pending with a dead worker — PRs #35–39.
- Chapter 6b: hunting 'database is locked'
Chapter 6, part 2: the SQLite lock hunt — wrong first hypothesis, instrumentation, transaction splits, retry_locked — PRs #40, #43.