chore: migrate to pnpm for package management and update CI configuration

- Replaced npm with pnpm in the CI configuration and Dockerfile for improved dependency management.
- Updated package.json to specify pnpm as the package manager.
- Modified installation instructions in README.md to reflect the use of pnpm.
- Enhanced the build process in the Dockerfile to utilize pnpm for installing dependencies and building the application.

README.md

@@ -16,28 +16,23 @@ By leveraging the latest features of **Next.js 14** and key functionalities like
 
 ## Installation
 
-1. Download/fork/clone the repo and Once you're in the correct directory, it's time to install all the necessary dependencies. You can do this by typing the following command:
+1. Download/fork/clone the repo and once you're in the correct directory, install all dependencies with:
 
 ```
-npm install
+pnpm install
 ```
-If you're using **Yarn** as your package manager, the command will be:
+If `pnpm` is not already available on your machine, enable it via Corepack first:
 
 ```
-yarn install
+corepack enable
+corepack prepare pnpm@10.18.0 --activate
 ```
 
-2. Okay, you're almost there. Now all you need to do is start the development server. If you're using **npm**, the command is:
+2. Start the development server:
 
 ```
-npm run dev
+pnpm dev
 ```
-And if you're using **Yarn**, it's:
-
-```
-yarn dev
-```
-
 And voila! You're now ready to start developing. **Happy coding**!
 
 ## Highlighted Features