- Add GET /{plan_id}/prep-session endpoint so frontend can retrieve existing sessions without creating
- Fix list_plans response_model from list[dict] to list[PlanSummary] with proper _plan_summary() mapping
- Replace assert in store.update_prep_task with ValueError (assert is stripped under python -O)
- Add day_of_week 0-6 validation to upsert_slot endpoint
- Remove MagicMock sqlite artifact files left by pytest (already in .gitignore)
- upsert_slot: raise 422 immediately if meal_type not in VALID_MEAL_TYPES
- update_prep_task: assert whitelist safety contract after dict comprehension
- CreatePlanRequest: week_start typed as date with must_be_monday validator; str() cast at call site
- PrepTask: frozen=True; build_prep_tasks rewired to use (priority, kwargs) tuples so frozen instances are built with correct sequence_order in one pass (no post-construction mutation)
- Move deferred import json to file-level in meal_plans.py
- Fix test dates: "2026-04-14" was a Tuesday; updated request bodies to "2026-04-13" (Monday)
