feat: Replace video demonstrations with GIFs in README

This commit updates the `README.md` to replace the video demonstrations (`.mp4` files) under the "Videos" section with GIF images.

The following changes were made:
- Removed the "Videos" section and its table of `.mp4` files.
- Added a new centered layout using `<p align="center">` to display GIF images.
- Deleted the following `.mp4` files from the `assets` directory:
    - `button-group.mp4`
    - `buttons.mp4`
    - `floating toolbar.mp4`
    - `progress indicator.mp4`
- Added the following new GIF files to the `assets` directory:
    - `button-group.gif`
    - `buttons.gif`
    - `floating-toolbar.gif`
    - `progress-indicator.gif`
- The "Screenshots" section header is now followed by the new GIF display.

Author: cavin-macwan

README.md

@@ -107,18 +107,12 @@ Explore the app to see these components in action!
 
 ## 🖼️ Screenshots
 
-## 🎥 Videos
-
-<table>
-  <tr>
-    <td><video src="assets/button-group.mp4" width="320" controls muted playsinline></video></td>
-    <td><video src="assets/buttons.mp4" width="320" controls muted playsinline></video></td>
-  </tr>
-  <tr>
-    <td><video src="assets/floating%20toolbar.mp4" width="320" controls muted playsinline></video></td>
-    <td><video src="assets/progress%20indicator.mp4" width="320" controls muted playsinline></video></td>
-  </tr>
-</table>
+<p align="center">
+  <img src="assets/button-group.gif" width="45%" />
+  <img src="assets/progress-indicator.gif" width="45%" /><br/>
+  <img src="assets/buttons.gif" width="45%" />
+  <img src="assets/floating-toolbar.gif" width="45%" />
+</p>
 
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