refactor(collections): rule evaluators take the real row; both 45-field converter twins deleted

checkRulesAgainstBook/evaluateRule and the service's EvaluateRules
existed in two parallel universes: one over database.MediaItems (what
every query actually returns) and one over ListMediaItemsRow (what two
hand-written 45-field mediaItemsToListMediaItemsRow converters
produced — verbatim twins in the handler and the dashboard service,
with a URL-resolution side effect baked into a "converter"). The rule
fields (genre/series/author/language/publisher/copyright_year/tags)
all exist on MediaItems, so the evaluators now take the real row and
the converters, their three call-site loops, and the dead
ApplyAutoAssignRules entry point (zero callers) are gone.

The rules surface is wire-covered by the collections rules scenarios;
handlers+services suites and the full pin/H1/H3 battery green.

internal/services/collection_service.go

@@ -509,7 +509,7 @@ func (s *CollectionService) mediaItemMatchesRule(item database.MediaItems, rule
 }
 
 // EvaluateRules evaluates auto-assign rules for a media item
-func (s *CollectionService) EvaluateRules(mediaItem database.ListMediaItemsRow, rules []Rule) []RuleEvaluation {
+func (s *CollectionService) EvaluateRules(mediaItem database.MediaItems, rules []Rule) []RuleEvaluation {
 	var evaluations []RuleEvaluation
 
 	// Sort rules by priority (higher priority first)
@@ -708,40 +708,6 @@ func (s *CollectionService) DeleteDeviceShelfMapping(ctx context.Context, mappin
 	return nil
 }
 
-// ApplyAutoAssignRules applies auto-assign rules for all collections to a media item
-func (s *CollectionService) ApplyAutoAssignRules(ctx context.Context, mediaItem database.ListMediaItemsRow, userID uuid.UUID) ([]uuid.UUID, error) {
-	var matchedCollectionIDs []uuid.UUID
-
-	collections, err := s.GetUserCollections(ctx, userID)
-	if err != nil {
-		return nil, fmt.Errorf("failed to get user collections: %v", err)
-	}
-
-	for _, collection := range collections {
-		if len(collection.AutoAssignRules) == 0 {
-			continue
-		}
-
-		var rules []Rule
-		if err := json.Unmarshal(collection.AutoAssignRules, &rules); err != nil {
-			continue
-		}
-
-		evaluations := s.EvaluateRules(mediaItem, rules)
-
-		// Check if any rules match
-		for _, eval := range evaluations {
-			if eval.Matches && eval.Confidence > 0.7 {
-				matchedCollectionIDs = append(matchedCollectionIDs, uuid.UUID(collection.ID.Bytes))
-				break
-			}
-		}
-	}
-
-	return matchedCollectionIDs, nil
-}
-
-// Helper functions (Go standard library functions)
 func toLower(s string) string {
 	if len(s) == 0 {
 		return s