fix(main.ts): import correct functions from utils module

feat(stage.ts): implement stage navigation functionality
feat(stageNav.ts): implement stage navigation overlay functionality
feat(state.ts): implement state management for index and threshold
feat(utils.ts): add utility functions for increment and decrement

assets/ts/resources.ts

@@ -0,0 +1,21 @@
+// data structure for images info
+export interface ImageJSON {
+  index: number
+  url: string
+  imgH: number
+  imgW: number
+  pColor: string
+  sColor: string
+}
+
+export function initResources(): ImageJSON[] {
+  const imagesJson = document.getElementById('imagesSource') as HTMLScriptElement
+  return JSON.parse(imagesJson.textContent as string).sort(
+    (a: ImageJSON, b: ImageJSON) => {
+      if (a.index < b.index) {
+        return -1
+      }
+      return 1
+    }
+  )
+}