refactor: move Pkl module definitions to dedicated package

pkg/nebula/worker/manifest.go

@@ -1 +0,0 @@
-package worker

pkg/nebula/worker/sync.go

@@ -0,0 +1,8 @@
+package worker
+
+import "github.com/labstack/echo/v4"
+
+func GetDatabaseSchema(e echo.Context) error {
+	// Implement database schema endpoint
+	return nil
+}

pkg/nebula/worker/wellknown.go

@@ -1 +0,0 @@
-package worker