feat: implement profile customization

[Subhash21022]

Related Issue

Closes #434

Summary

Implemented a Notion-inspired Profile & Workspace Customization system. This allows users to heavily personalize their dashboard with custom banners, avatars, themes, and layouts, creating a more engaging and personalized study environment.

Changes Made

• Notion-Style Profile Interface: Created a new dedicated Profile section (index.html) featuring a customizable cover banner and circular avatar.
• Banner & Avatar Management: Added the ability for users to upload custom images/GIFs for their banner and avatar. Also included a gallery of beautiful default preset covers.
• Theme Customization: Implemented Dark Mode, Light Mode, and a new AMOLED (true black) mode.
• Accent Colors & Typography: Added 6 customizable UI accent colors and 4 different font family choices (Inter, Roboto, Space Grotesk, Comic Sans).
• Dashboard Layout Editor: Users can now toggle specific dashboard widgets on or off (Calendar, Tasks, Focus Mode, Statistics) to reduce clutter based on their workflow.
• Database & API Integration: Updated server.js and database.js with new /api/profile endpoints and a user_profiles SQLite table to ensure all custom settings persist across sessions.
• Optimized Uploads: Added .gitignore rules to prevent test user uploads (public/uploads/) from cluttering the repository.

Testing

• Tested locally by running npm start and accessing localhost:3000.
• Verified that uploaded files correctly save to the local file system using multer.
• Verified that all profile settings (theme, fonts, layout) properly sync with the SQLite database and instantly apply when the page is reloaded or when the user logs in.
• Confirmed that layout toggling correctly hides/shows dashboard sections without breaking grid alignments.

Screenshots

Checklist

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

[Subhash21022]

@Charushi06 Please review