- Extract readJSONFile + writeJSONAtomic in cache.go; category cache
reuses them (saveCategoryCache is one line, loadCategoryCache uses
the standard load-or-empty shape).
- Drop dead errMsg param from scoreCategoryResult (always "").
- Wrap writeCategoryReport errors with context for consistency.
- Wrap runSimilarityMode / runCategoryMode's 5 per-mode flags into an
evalConfig struct so params don't drift.
- Promote validModes to a package-level var.
- Remove redundant cache = new...() fallback after load* (both load
helpers already return a non-nil empty cache on error).
- Strip narrating / diff-referencing comments per CLAUDE.md; keep the
one genuine WHY on normalizeCategory (divergence from normalize.Name).
Net -54 lines across 4 files; go build + go vet + tests green.
vikingowl
126cc58cbf