Backend layer for the v3 decision tree:
- internal/services/event_category_service.go (NEW)
- Tree(): nested tree of all active event_categories for the
Pathway B / B1 cascade UI. Uses single SELECT + in-memory
parent-child stitching; corpus is small (≤100 nodes).
- ConceptsForSlug(): recursive CTE walks descendants of a slug and
joins event_category_concepts to return the candidate concept
outcomes (with optional proceeding_type_code narrowing).
- ConceptIDsForSlug(): convenience reduction for
`WHERE concept_id = ANY(...)` queries against the existing
deadline_search matview.
- ProceedingCodesForSlug(): per-leaf proceeding-code narrowing for
Phase D's forum filter intersection.
- internal/handlers/fristenrechner_event_categories.go (NEW)
- GET /api/tools/fristenrechner/event-categories returning the
nested tree as JSON. Frontend will ETag-cache via localStorage.
- Wired EventCategory into handlers.Services + dbServices + main.go.
The existing /api/tools/fristenrechner/search handler stays
unchanged in this commit; Phase D will add ?event_category_slug=
and ?forum= query params on top.
Build + vet clean.
2c770ef02f