Background grounding and recipe fix-up API (#90)

Co-authored-by: dev_agent <dev_agent@cubecraftlabs.com>

migrations/0009_dinner_grounding_error.sql

@@ -0,0 +1,7 @@
+-- 0009_dinner_grounding_error: a dinner whose grounding failed keeps why,
+-- as one of the reason codes package dinners defines (no_recipe_found,
+-- recipe_unusable, search_not_configured, search_failed, ai_failed,
+-- interrupted, grounding_error). It is NULL unless grounding_status is
+-- failed.
+
+ALTER TABLE dinners ADD COLUMN grounding_error TEXT;