feat(P04): variants API + TS types (Wave 3)
Task 4-3-01: POST /v1/variants (template_id or competency_id resolution; cache-first
D-029; 404 unknown template/competency; 422 neither), GET /v1/variants/{task_id},
GET /v1/variants?learner_id=. SQLiteVariantStore + VariantGenerator wired into lifespan.
Task 4-3-02: packages/types/variants.ts (TaskVariant, VariantParams) + grading.ts
(RubricScore + GradeRecord, criteria-typed) — field-for-field Python parity,
scores typed as the documented rubric-or-gate union.
11 endpoint tests green (distinct learners -> distinct statements at API level; cache
hit -> zero LLM calls); suite 324 green; typecheck 7/7; ruff clean.
---ci---
phase: 4
milestone: v0.3
status: execute
requirements: {covered: [REQ-3-005], partial: []}
---/ci---
CIAgent
4acffac71e