feat(modpacks): implement simple zip importer and API

internal/database/modpack_repository.go

@@ -0,0 +1,49 @@
+// File: backend/internal/database/modpack_repository.go
+package database
+
+import (
+	"context"
+
+	"gitea.mrixs.me/minecraft-platform/backend/internal/models"
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+type ModpackRepository struct {
+	DB *pgxpool.Pool // <--- ИЗМЕНЕНИЕ
+}
+
+// CreateModpackTx создает модпак и все его файлы в одной транзакции.
+func (r *ModpackRepository) CreateModpackTx(ctx context.Context, modpack *models.Modpack, files []models.ModpackFile) error {
+	tx, err := r.DB.Begin(ctx)
+	if err != nil {
+		return err
+	}
+	defer tx.Rollback(ctx)
+
+	var modpackID int
+	err = tx.QueryRow(ctx,
+		"INSERT INTO modpacks (name, display_name, minecraft_version) VALUES ($1, $2, $3) RETURNING id",
+		modpack.Name, modpack.DisplayName, modpack.MinecraftVersion,
+	).Scan(&modpackID)
+	if err != nil {
+		return err
+	}
+
+	rows := make([][]interface{}, len(files))
+	for i, f := range files {
+		rows[i] = []interface{}{modpackID, f.RelativePath, f.FileHash, f.FileSize, f.DownloadURL}
+	}
+
+	_, err = tx.CopyFrom(
+		ctx,
+		pgx.Identifier{"modpack_files"},
+		[]string{"modpack_id", "relative_path", "file_hash", "file_size", "download_url"},
+		pgx.CopyFromRows(rows),
+	)
+	if err != nil {
+		return err
+	}
+
+	return tx.Commit(ctx)
+}