feat: implement rule application engine with full-text variant support, batch entry processing, and tag visualization in UI.

internal/db/db.go

@@ -725,6 +725,22 @@ func (d *DB) ListEntries(filter EntryFilter) ([]models.FeedEntry, int, error) {
 		entries = append(entries, e)
 	}
 
+	// Batch-load variants for all returned entries
+	if len(entries) > 0 {
+		ids := make([]string, len(entries))
+		for i, e := range entries {
+			ids[i] = e.ID
+		}
+		variantMap, err := d.batchLoadVariants(ids)
+		if err == nil {
+			for i := range entries {
+				if v, ok := variantMap[entries[i].ID]; ok {
+					entries[i].Variants = v
+				}
+			}
+		}
+	}
+
 	return entries, total, nil
 }
 
@@ -810,6 +826,55 @@ func (d *DB) ListVariantsForEntry(entryID string) (map[string]models.EntryVarian
 	return variants, nil
 }
 
+// batchLoadVariants loads lightweight variants (tags, ai_summary keys, etc.) for multiple entries.
+// Excludes large text variants like readability_full_text for performance.
+func (d *DB) batchLoadVariants(entryIDs []string) (map[string]map[string]models.EntryVariant, error) {
+	if len(entryIDs) == 0 {
+		return nil, nil
+	}
+	placeholders := make([]string, len(entryIDs))
+	args := make([]interface{}, len(entryIDs))
+	for i, id := range entryIDs {
+		placeholders[i] = "?"
+		args[i] = id
+	}
+	query := `
+		SELECT entry_id, variant_key, content_type,
+		       CASE WHEN variant_key IN ('readability_full_text') THEN '' ELSE COALESCE(text_value, '') END,
+		       COALESCE(blob_path, ''), metadata, created_at, updated_at
+		FROM entry_variants
+		WHERE entry_id IN (` + strings.Join(placeholders, ",") + `)
+	`
+	rows, err := d.Query(query, args...)
+	if err != nil {
+		return nil, err
+	}
+	defer func() {
+		_ = rows.Close()
+	}()
+
+	result := make(map[string]map[string]models.EntryVariant)
+	for rows.Next() {
+		var v models.EntryVariant
+		var metaStr sql.NullString
+		err := rows.Scan(
+			&v.EntryID, &v.VariantKey, &v.ContentType, &v.TextValue, &v.BlobPath, &metaStr, &v.CreatedAt, &v.UpdatedAt,
+		)
+		if err != nil {
+			return nil, err
+		}
+		v.Metadata = make(map[string]interface{})
+		if metaStr.Valid && metaStr.String != "" {
+			_ = json.Unmarshal([]byte(metaStr.String), &v.Metadata)
+		}
+		if result[v.EntryID] == nil {
+			result[v.EntryID] = make(map[string]models.EntryVariant)
+		}
+		result[v.EntryID][v.VariantKey] = v
+	}
+	return result, nil
+}
+
 func (d *DB) SetVariant(v models.EntryVariant) error {
 	now := time.Now().UTC()
 	metaBytes, _ := json.Marshal(v.Metadata)