chore: Update npm dependencies and fix WebSocket import in server.js

[LightYagami28]

Description

This pull request includes several updates to improve the codebase of the KindleCalendar project. The changes encompass enhancements to JavaScript syntax, Python script organization, and server-side JavaScript code clarity.

Changes

client.js:

• Updated JavaScript syntax to use arrow functions, let and const instead of var, and template literals for string interpolation.
• Improved event handling by using addEventListener instead of assigning event handlers directly to properties like onclick.
• Enhanced error handling and readability.

screenshot.py:

• Grouped imported modules together at the top of the script.
• Followed PEP8 naming conventions for variables and function names.
• Improved code comments for better readability and understanding.
• Used f-strings for string formatting.
• Utilized a dictionary for mapping day names to offsets.
• Removed unnecessary imports and commented-out code.
• Updated code formatting to be consistent.

server.js:

• Changed the import statement for WebSocket from require('ws-plus-hixie') to require('ws').
• Renamed the WsHixie variable to WebSocket for clarity.
• Used let and const instead of var.
• Updated the watcher.on('change') callback function to use let instead of var for the now variable.
• Applied consistent semicolon usage.
• Improved readability by adding comments to clarify code blocks.

These changes aim to enhance the maintainability, readability, and efficiency of the KindleCalendar project.

Checklist

• [x] Updated JavaScript syntax in client.js
• [x] Organized Python imports and followed PEP8 conventions in screenshot.py
• [x] Refactored server.js for clarity and consistency
• [x] Checked and tested the functionality of the updated code
• [x] Updated the documentation and included a changelog