## [2026-05-11] Stream 5 analysis: tools/ package split evaluation
Completed detailed cross-file dependency audit of tools/ using gosymdb.
Key finding: the `calls_*` group (13 files, 4563 lines) has **zero DB
dependency** and is completely filesystem-based, making it the cleanest
possible split boundary.

Real cross-domain dependencies are minimal:
- `parallel_aggregate.go` → `ClusteredCall` type (move type to shared)
- `crud/*`, `import/*` → `resolveDBPath()` (move to db/)
- `calls_from_*` → `AviaNZLabel/Meta/Segment` (stay together in calls/)
- `calls_classify`, `calls_clip` → `IsNight` (move isnight to calls/)
No code changes made — analysis only. Updated PLAN.md with split proposal.