feat(in_app_help): support folder icons

src/services/in_app_help.spec.ts

@@ -0,0 +1,41 @@
+import { describe, expect, expectTypeOf, it } from "vitest";
+import { parseNoteMeta } from "./in_app_help.js";
+import type NoteMeta from "./meta/note_meta.js";
+
+describe("In-app help", () => {
+
+    it("preserves custom folder icon", () => {
+        const meta: NoteMeta = {
+            "isClone": false,
+            "noteId": "yoAe4jV2yzbd",
+            "notePath": [
+                "OkOZllzB3fqN",
+                "yoAe4jV2yzbd"
+            ],
+            "title": "Features",
+            "notePosition": 40,
+            "prefix": null,
+            "isExpanded": false,
+            "type": "text",
+            "mime": "text/html",
+            "attributes": [
+                {
+                    "type": "label",
+                    "name": "iconClass",
+                    "value": "bx bx-star",
+                    "isInheritable": false,
+                    "position": 10
+                }
+            ],
+            "format": "html",
+            "attachments": [],
+            "dirFileName": "Features",
+            "children": []
+        };
+
+        const item = parseNoteMeta(meta, "/");
+        const icon = item.attributes?.find((a) => a.name === "iconClass");
+        expect(icon?.value).toBe("bx bx-star");
+    });
+
+});