fix: properly escape special characters in CSV exports

[yamuna898]

Related Issue

Closes #996

Summary

Fixes an issue where CSV exports became malformed when task fields contained commas or quotation marks.

Changes Made

• Added a dedicated CSV field escaping helper.
• Escaped task title, subject, status, notes, and other exported fields.
• Ensured commas inside values do not create additional columns.
• Preserved quotation marks according to CSV formatting rules.

Testing

Tested locally with the following values:

• React, Node and Express Revision
• Hello "World"
• Notes containing commas and quotation marks

Verified that:

• Exported CSV files open correctly in Excel.
• Values remain inside a single cell.
• Quotation marks are preserved correctly.
• No column shifting occurs.

Screenshots

Before Fix

• Task titles containing commas were split across multiple columns in Excel.

After Fix

• Values containing commas and quotation marks remain within a single cell.

Checklist

• Code follows project style
• Tested locally
• No unrelated changes included
• Documentation updated (if applicable)