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

app.go

@@ -0,0 +1,27 @@
+package main
+
+import (
+	"context"
+	"fmt"
+)
+
+// App struct
+type App struct {
+	ctx context.Context
+}
+
+// NewApp creates a new App application struct
+func NewApp() *App {
+	return &App{}
+}
+
+// startup is called when the app starts. The context is saved
+// so we can call the runtime methods
+func (a *App) startup(ctx context.Context) {
+	a.ctx = ctx
+}
+
+// Greet returns a greeting for the given name
+func (a *App) Greet(name string) string {
+	return fmt.Sprintf("Hello %s, It's show time!", name)
+}