[GOOD FIRST ISSUE] Update .gitignore to ignore backup and sensitive files

[github-actions]

Task Description

Developers sometimes accidentally commit .env.local.backup or similar local test files.

What You Need to Know

• Relevant file(s): .gitignore
• Concepts involved: Git configuration

Steps to Complete

1. Open the .gitignore file in the root.
2. Add patterns for *.backup, *.bak, and .env* to ensure no sensitive files leak.

Resources

• If this touches UI: read DESIGN.md first — it has all colors, spacing, typography, and component specs

Definition of Done

• Task is complete
• Tests pass (if applicable)
• PR opened and linked to this issue

[Aditya8369]

@PRODHOSH please assign me