refactor: replace standard log with zap logger and optimize code patterns

- Migrate all log.Printf/log.Println calls to structured zap logging
- Use cmp.Or for cleaner default value handling
- Replace manual loops with slices.ContainsFunc/IndexFunc
- Add batch query methods (IsLikedBatch, IsFavoritedBatch) to solve N+1 problem
- Update JSON tags from omitempty to omitzero for numeric fields
- Use errgroup-style wg.Go for worker goroutines
- Remove duplicate casbin/v2 dependency (keeping v3)
- Add plans/ to gitignore

cmd/migrate/main.go

@@ -1,10 +1,12 @@
 package main
 
 import (
+	"errors"
 	"flag"
 	"fmt"
 	"log"
 
+	"go.uber.org/zap"
 	"gorm.io/driver/postgres"
 	"gorm.io/gorm"
 )
@@ -73,17 +75,17 @@ func main() {
 	defer sqlDB.Close()
 
 	if err := sqlDB.Ping(); err != nil {
-		log.Fatalf("Failed to ping database: %v", err)
+		zap.L().Fatal("Failed to ping database", zap.Error(err))
 	}
 
-	log.Println("Connected to database")
+	zap.L().Info("Connected to database")
 
 	// 运行迁移
 	if err := runMigration(db); err != nil {
-		log.Fatalf("Migration failed: %v", err)
+		zap.L().Fatal("Migration failed", zap.Error(err))
 	}
 
-	log.Println("Migration completed successfully")
+	zap.L().Info("Migration completed successfully")
 }
 
 func runMigration(db *gorm.DB) error {
@@ -105,26 +107,31 @@ func runMigration(db *gorm.DB) error {
 	}
 
 	if hasPreviewURL && hasPreviewURLLarge {
-		log.Println("Columns already exist, skipping migration")
+		zap.L().Info("Columns already exist, skipping migration")
 		return nil
 	}
 
 	// 添加字段
+	var errs []error
 	if !hasPreviewURL {
-		log.Println("Adding preview_url column...")
+		zap.L().Info("Adding preview_url column...")
 		if err := db.Exec("ALTER TABLE post_images ADD COLUMN preview_url TEXT").Error; err != nil {
-			return fmt.Errorf("failed to add preview_url column: %w", err)
+			errs = append(errs, fmt.Errorf("failed to add preview_url column: %w", err))
 		}
 	}
 
 	if !hasPreviewURLLarge {
-		log.Println("Adding preview_url_large column...")
+		zap.L().Info("Adding preview_url_large column...")
 		if err := db.Exec("ALTER TABLE post_images ADD COLUMN preview_url_large TEXT").Error; err != nil {
-			return fmt.Errorf("failed to add preview_url_large column: %w", err)
+			errs = append(errs, fmt.Errorf("failed to add preview_url_large column: %w", err))
 		}
 	}
 
-	log.Println("Migration completed successfully")
+	if len(errs) > 0 {
+		return errors.Join(errs...)
+	}
+
+	zap.L().Info("Migration completed successfully")
 	return nil
 }