Feature req addition of text formatting tools #15

[adithyen]

📌 Description

Brief description of what this PR does.
This PR addresses Issue #15 by adding basic text formatting tools to the NoteStack application. It allows users to create notes with visual hierarchy and emphasis, making long notes easier to read.

🔗 Related Issue

Closes #15

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🛠 Changes Made

-Added a formatting toolbar (Bold, Italic, Bullet List) above the note input in [index.html].

• Converted the note input textarea to a contenteditable div in [index.html] to support rich-text HTML rendering.
• Updated [script.js] to use document.execCommand() for formatting actions and to save/render innerHTML instead of plain text for notes.
• Added styling for the new toolbar and contenteditable area in [style.css], including full support for Dark Mode.

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📷 Screenshots (if applicable)

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✅ Checklist

• I have tested my changes
• My code follows project guidelines
• I have linked the related issue