[Feature] Sample env file in the Codebase

# 🚀 Feature Request: Add a `.env.sample` File

## Description

Introduce a `.env.sample` file to the repository to standardize and simplify the setup process for managing environment variables.

## Motivation

Managing environment variables without a clear template can be challenging, especially for new developers. The absence of a `.env.sample` file leads to confusion about:
- Which variables are required.
- The purpose of each variable.
- The expected format or example values.

Adding a `.env.sample` file will streamline onboarding and reduce errors caused by misconfigured or missing variables.

## Proposed Solution

Create a `.env.sample` file in the root of the repository with the following:
- Placeholders for all required environment variables.
- Comments explaining the purpose of each variable.
- Example values (if applicable).

### Example

```env
# Required API key for authentication
API_KEY=your_api_key_here

# RPC endpoint URL
RPC_URL=https://your.rpc.url

# Private key for signing transactions
PRIVATE_KEY=your_private_key