Add SQLite persistence, import-snapshot tool, and karma functionality

server/cmd/import-snapshot/main.go

@@ -0,0 +1,56 @@
+package main
+
+import (
+	"encoding/json"
+	"flag"
+	"log"
+	"os"
+
+	"lunar-tear/server/internal/database"
+	"lunar-tear/server/internal/store"
+	"lunar-tear/server/internal/store/sqlite"
+)
+
+func main() {
+	dbPath := flag.String("db", "db/game.db", "SQLite database path")
+	snapshotPath := flag.String("snapshot", "", "Path to JSON snapshot file (required)")
+	userUuid := flag.String("uuid", "", "UUID to assign to the imported user (must match the client's UUID)")
+	flag.Parse()
+
+	if *snapshotPath == "" {
+		log.Fatal("--snapshot flag is required")
+	}
+	if *userUuid == "" {
+		log.Fatal("--uuid flag is required")
+	}
+
+	data, err := os.ReadFile(*snapshotPath)
+	if err != nil {
+		log.Fatalf("read snapshot: %v", err)
+	}
+	log.Printf("read %d bytes from %s", len(data), *snapshotPath)
+
+	var u store.UserState
+	if err := json.Unmarshal(data, &u); err != nil {
+		log.Fatalf("unmarshal snapshot: %v", err)
+	}
+	u.EnsureMaps()
+	u.Uuid = *userUuid
+
+	log.Printf("parsed user %d (uuid=%s, costumes=%d, weapons=%d, characters=%d, quests=%d)",
+		u.UserId, u.Uuid, len(u.Costumes), len(u.Weapons), len(u.Characters), len(u.Quests))
+
+	db, err := database.Open(*dbPath)
+	if err != nil {
+		log.Fatalf("open database: %v", err)
+	}
+	defer db.Close()
+
+	userStore := sqlite.New(db, nil)
+
+	if err := userStore.ImportUser(&u); err != nil {
+		log.Fatalf("import user: %v", err)
+	}
+
+	log.Printf("imported user %d successfully", u.UserId)
+}