Rank stored candidates instead of reusing them first

Ground returned the first search result that was already stored before
fetching or ranking anything, so an unrelated stored recipe could win
over a relevant new one. Ground now ranks every candidate and walks the
ranking best first, reusing a stored recipe only at its ranked place.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/recipes/ground.go

@@ -102,11 +102,11 @@ func NewGrounder(st *store.Store, search SearchSource, pages PageFetcher, photos
 }
 
 // Ground searches for query and grounds dishName in the best recipe found.
-// When one of the top RankDepth candidates is already stored, the first
-// such is returned without fetching anything. Otherwise the candidates are
-// ranked (see Rank) and tried best first: the first whose photo can be
-// cached and whose ingredients normalize is stored — the recipe, its
-// ingredients, steps and photo in one transaction — and returned.
+// The candidates are ranked (see Rank) and tried best first: a candidate
+// already stored is returned as it is, and otherwise the first whose photo
+// can be cached and whose ingredients normalize is stored — the recipe, its
+// ingredients, steps and photo in one transaction — and returned. A stored
+// recipe is reused only when it ranks above every candidate that grounds.
 //
 // When no candidate grounds the dish the error is an *ErrUngroundable with
 // each reason. A failure that is not the candidates' — the search, the
@@ -126,12 +126,6 @@ func (g *Grounder) Ground(ctx context.Context, dishName, query string) (Grounded
 	if len(cands) == 0 {
 		return Grounded{}, &ErrUngroundable{Target: dishName, Reasons: []error{ErrNoCandidates}}
 	}
-	for _, c := range cands {
-		if gr, ok, err := g.stored(ctx, c.URL); err != nil || ok {
-			return gr, err
-		}
-	}
-
 	ranked, rankErr := Rank(ctx, g.pages, dishName, cands)
 	if err := ctx.Err(); err != nil {
 		return Grounded{}, err
@@ -141,6 +135,9 @@ func (g *Grounder) Ground(ctx context.Context, dishName, query string) (Grounded
 		reasons = append(reasons, rankErr)
 	}
 	for _, r := range ranked {
+		if gr, ok, err := g.stored(ctx, r.Candidate.URL); err != nil || ok {
+			return gr, err
+		}
 		gr, reason, err := g.ground(ctx, r.Candidate.URL, r.Recipe)
 		if err != nil {
 			return Grounded{}, fmt.Errorf("recipes: ground %q: %w", dishName, err)