Add GroceryLink schema model and grocery_links field to RecipeResult.
Introduce GroceryLinkBuilder service (Amazon Fresh, Walmart, Instacart)
using env-var affiliate tags; no links emitted when tags are absent.
Wire link builder into RecipeEngine.suggest() for levels 1-2.
Add test_grocery_links_free_tier to verify structure contract.
35 tests passing.
Uses circuitforge_core.tasks.scheduler. VRAM detection via cf-orch when
available, falling back to unlimited. Adds expiry_llm_fallback task type
to background-predict expiry dates for items the LUT doesn't cover.
