Hide the recipe link, pick the creating suggestion, refuse duplicate positions

Dinner detail review fixes for GET /api/v1/dinners/{id}:

- source is now {site_name} with no url. A stored source_url may be a
  pasted or offered link carrying a personal token, and nothing can show
  a stored link is free of one; the candidate flow keeps every page URL
  on the server for the same reason, so the detail does too.
- why_picked comes from GetDinnerSuggestionReasons, which reads only
  pending or accepted suggestions: a suggestion is only ever created with
  a new dinner and declining one archives that dinner, so a declined row
  never created a live dinner. More than one candidate row is an error
  rather than a guess. sqlc regenerated.
- Two recipe ingredients or steps at one position leave recipe order
  unknown, so the read fails rather than ordering them by id.

Maestro task 099e9952-7f98-4700-8369-241c589a1e9d.

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

internal/db/querier.go

@@ -103,9 +103,13 @@ type Querier interface {
 	// Returns sql.ErrNoRows until the row exists.
 	GetChatSettings(ctx context.Context) (ChatSetting, error)
 	GetDinner(ctx context.Context, id string) (Dinner, error)
-	// The reason of the suggestion that created dinner_id, its earliest.
-	// Returns sql.ErrNoRows for a dinner no suggestion created.
-	GetDinnerSuggestionReason(ctx context.Context, dinnerID string) (string, error)
+	// The reason of each suggestion of dinner_id that can have created it,
+	// none for a dinner no suggestion created. A suggestion is only ever
+	// created with a new dinner, and declining one archives its dinner, so a
+	// live dinner's creating suggestion is pending (the dinner still
+	// suggested) or accepted; a declined one did not create it. More than one
+	// row means nothing records which did.
+	GetDinnerSuggestionReasons(ctx context.Context, dinnerID string) ([]string, error)
 	// Returns sql.ErrNoRows until the row exists.
 	GetHouseholdSettings(ctx context.Context) (HouseholdSetting, error)
 	// Returns sql.ErrNoRows until the row exists.