feat: load explicit configuration references and remove implicit env overlays

examples/platform/main.go

@@ -88,16 +88,9 @@ func newApp(cfg omni.Config, d dependencies) (*omni.App, error) {
 	return app, nil
 }
 func run(ctx context.Context, configFile, root string) error {
-	var cfg config.Config
-	var err error
-	if configFile != "" {
-		cfg, err = config.LoadFile(configFile, "")
-	} else {
-		cfg, err = config.LoadFromEnv("")
-		if os.Getenv("GO_OMNI_HTTP_ADDR") == "" {
-			cfg.Address = "127.0.0.1:8080"
-		}
-	}
+	defaults := config.Default()
+	defaults.Address = "127.0.0.1:8080"
+	cfg, err := config.LoadProject(configFile, defaults)
 	if err != nil {
 		return err
 	}