- `tech-tree-layout.int.spec.ts`: pure layout (wrapping, manual overrides,
category bands, forward-edge warnings, cycles, catalog-stability).
- `tech-tree-prereq-edits.int.spec.ts`: add/remove/switch prerequisites with
cycle rejection and the pin-on-connect stability contract.
- `tech-tree-stability.int.spec.ts`: freeze pins every relocated card on a
data change, plus edge visuals (per-path colors, per-source lanes).
- `tech-categories.int.spec.ts`: CRUD, RBAC, division gating, FK set-null,
position round-trip.
- `tech-tree.e2e.spec.ts`: nav entry, render, preview/panel edits, both
quick-create paths, drag persistence + Auto-arrange, save positions
surviving a reload, connect/disconnect, and multi-column wrapping.
