docs: update README with quick demo references and remove outdated instructions

Author: manu4543

README.md

@@ -338,17 +338,9 @@ imagekit.upload({
 
 ## Demo Application
 
-For the fastest way to get started, check out the demo application in the [samples/sample-app](https://github.com/imagekit-developer/imagekit-javascript/tree/master/samples/sample-app) folder.
-
-To run the demo locally:
-```bash
-git clone https://github.com/imagekit-developer/imagekit-javascript.git
-cd imagekit-javascript
-```
-Then, create a `.env` file in the `samples/sample-app` directory based on `sample.env` and provide your `PRIVATE_KEY`, `PUBLIC_KEY`, and `URL_ENDPOINT` from your ImageKit dashboard. Finally, start the demo:
-```bash
-yarn startSampleApp
-```
+For a quick demonstration of the SDK features, refer to our test examples:
+- URL Generation examples can be found in [test/url-generation.js](./test/url-generation.js)
+- File Upload examples can be found in [test/upload.js](./test/upload.js)
 
 ## Changelog
 

test/url-generation.js

@@ -867,6 +867,7 @@ describe("URL generation", function () {
         expect(url).equal(`https://ik.imagekit.io/test_url_endpoint/tr:yc-40/test_path1.jpg`);
     });
 
+    // This is done just to test how SDK constructs URL, the actual transformation is not valid.
     it('Including deprecated properties', function () {
         const url = imagekit.url({
             path: "/test_path.jpg",
@@ -906,6 +907,7 @@ describe("URL generation", function () {
         expect(url).equal(`https://ik.imagekit.io/test_url_endpoint/tr:h-300,w-400,ar-4-3,q-40,c-force,cm-extract,fo-left,f-jpeg,r-50,bg-A94D34,b-5-A94D34,rt-90,bl-10,n-some_name,pr-true,lo-true,t-5,md-true,cp-true,di-folder@@file.jpg,dpr-3,e-sharpen-10,e-usm-2-2-0.8-0.024,e-contrast,e-grayscale,e-shadow-bl-15_st-40_x-10_y-N5,e-gradient-from-red_to-white,orig-true,h-200,w-300,l-image,i-logo.png,l-end/test_path.jpg`);
     });
 
+    // This is done just to test how SDK constructs URL, the actual transformation is not valid
     it('should generate the correct URL when comprehensive transformations, including video and AI transformations, are applied', function () {
         const url = imagekit.url({
             path: "/test_path.jpg",