refactor: Flatten directory structure

Move project files from uzdb/ subdirectory to root directory for cleaner project structure.

Changes:
- Move frontend/ to root
- Move internal/ to root
- Move build/ to root
- Move all config files (go.mod, wails.json, etc.) to root
- Remove redundant uzdb/ subdirectory nesting

Project structure is now:
├── frontend/        # React application
├── internal/        # Go backend
├── build/           # Wails build assets
├── doc/             # Design documentation
├── main.go          # Entry point
└── ...

🤖 Generated with Qoder

main.go

@@ -0,0 +1,197 @@
+package main
+
+import (
+	"context"
+	"embed"
+	"fmt"
+	"os"
+	"path/filepath"
+	"time"
+
+	"github.com/wailsapp/wails/v2"
+	"github.com/wailsapp/wails/v2/pkg/options"
+	"github.com/wailsapp/wails/v2/pkg/options/assetserver"
+	"go.uber.org/zap"
+
+	"uzdb/internal/app"
+	"uzdb/internal/config"
+	"uzdb/internal/database"
+	"uzdb/internal/handler"
+	"uzdb/internal/services"
+)
+
+//go:embed all:frontend/dist
+var assets embed.FS
+
+// application holds the global application state
+type application struct {
+	app           *app.App
+	config        *config.Config
+	connManager   *database.ConnectionManager
+	encryptSvc    *services.EncryptionService
+	connectionSvc *services.ConnectionService
+	querySvc      *services.QueryService
+	httpServer    *handler.HTTPServer
+}
+
+func main() {
+	// Initialize application
+	appState, err := initApplication()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Failed to initialize application: %v\n", err)
+		os.Exit(1)
+	}
+
+	// Create Wails app with options
+	err = wails.Run(&options.App{
+		Title:  "uzdb",
+		Width:  1024,
+		Height: 768,
+		AssetServer: &assetserver.Options{
+			Assets: assets,
+		},
+		BackgroundColour: &options.RGBA{R: 27, G: 38, B: 54, A: 1},
+		OnStartup: func(ctx context.Context) {
+			appState.app.OnStartup(ctx)
+		},
+		OnShutdown: func(ctx context.Context) {
+			appState.app.Shutdown()
+		},
+		Bind: []interface{}{
+			appState.app,
+		},
+	})
+
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error running application: %v\n", err)
+		os.Exit(1)
+	}
+}
+
+// initApplication initializes all application components
+func initApplication() (*application, error) {
+	appState := &application{}
+
+	// Determine data directory
+	dataDir, err := getDataDirectory()
+	if err != nil {
+		return nil, fmt.Errorf("failed to get data directory: %w", err)
+	}
+
+	// Initialize configuration
+	cfg, err := config.Init(dataDir)
+	if err != nil {
+		return nil, fmt.Errorf("failed to initialize config: %w", err)
+	}
+	appState.config = cfg
+
+	logger := config.GetLogger()
+	logger.Info("initializing application", zap.String("data_dir", dataDir))
+
+	// Initialize encryption service
+	encryptSvc, err := services.InitEncryptionService(&cfg.Encryption)
+	if err != nil {
+		logger.Error("failed to initialize encryption service", zap.Error(err))
+		return nil, fmt.Errorf("failed to initialize encryption: %w", err)
+	}
+	appState.encryptSvc = encryptSvc
+
+	// Initialize SQLite database (for app data)
+	sqliteDB, err := database.InitSQLite(cfg.Database.SQLitePath, &cfg.Database)
+	if err != nil {
+		logger.Error("failed to initialize SQLite", zap.Error(err))
+		return nil, fmt.Errorf("failed to initialize database: %w", err)
+	}
+
+	// Initialize connection manager
+	appState.connManager = database.NewConnectionManager()
+
+	// Initialize services
+	appState.connectionSvc = services.NewConnectionService(
+		sqliteDB,
+		appState.connManager,
+		encryptSvc,
+	)
+
+	appState.querySvc = services.NewQueryService(sqliteDB)
+
+	// Initialize HTTP server (for debugging/API access)
+	appState.httpServer = handler.NewHTTPServer(
+		appState.connectionSvc,
+		appState.querySvc,
+	)
+
+	// Initialize Wails app wrapper
+	appState.app = app.NewApp()
+	appState.app.Initialize(
+		cfg,
+		appState.connectionSvc,
+		appState.querySvc,
+		appState.httpServer,
+	)
+
+	logger.Info("application initialized successfully")
+
+	return appState, nil
+}
+
+// getDataDirectory returns the appropriate data directory based on platform
+func getDataDirectory() (string, error) {
+	// Check environment variable first
+	if envDir := os.Getenv("UZDB_DATA_DIR"); envDir != "" {
+		return envDir, nil
+	}
+
+	var dataDir string
+
+	// Platform-specific directories
+	switch os.Getenv("GOOS") {
+	case "windows":
+		appData := os.Getenv("APPDATA")
+		if appData == "" {
+			return "", fmt.Errorf("APPDATA environment variable not set")
+		}
+		dataDir = filepath.Join(appData, "uzdb")
+
+	case "darwin": // macOS
+		homeDir, err := os.UserHomeDir()
+		if err != nil {
+			return "", err
+		}
+		dataDir = filepath.Join(homeDir, "Library", "Application Support", "uzdb")
+
+	default: // Linux and others
+		// Try XDG data directory
+		xdgData := os.Getenv("XDG_DATA_HOME")
+		if xdgData != "" {
+			dataDir = filepath.Join(xdgData, "uzdb")
+		} else {
+			homeDir, err := os.UserHomeDir()
+			if err != nil {
+				return "", err
+			}
+			dataDir = filepath.Join(homeDir, ".local", "share", "uzdb")
+		}
+	}
+
+	// For development, use local directory
+	if _, err := os.Stat("frontend"); err == nil {
+		dataDir = "./data"
+	}
+
+	// Ensure directory exists
+	if err := os.MkdirAll(dataDir, 0755); err != nil {
+		return "", fmt.Errorf("failed to create data directory: %w", err)
+	}
+
+	return dataDir, nil
+}
+
+// Helper functions exposed for testing
+func GetVersion() string {
+	return "1.0.0"
+}
+
+func GetBuildTime() string {
+	return time.Now().Format(time.RFC3339)
+}