feat(app): next-15 basic migration to next-15 from 14 with build fixes

[turingAlan]

migrated from next-14 to next-15 as it provides better native support for PWA internally in the framework

Title: next-15 basic migration to next-15 from 14 with build fixes

Description: This PR migrates the project from Next.js 14 to Next.js 15 to leverage its improved native support for Progressive Web Apps (PWAs) directly within the framework. The migration eliminates the need for external dependencies like next-pwa, marking the first step toward enhancing PWA capabilities in our web application.

Key changes include:

• Successfully resolved all migration-related issues, such as updating outdated dependencies (e.g., next-themes and yoopta) to compatible versions.
• Conducted basic testing to ensure functionality remains intact post-migration.
• Verified that the build process works seamlessly by running it locally—both building and running the application were successful.

Notes:

• I have not upgraded to React 19 at this stage. An attempt to upgrade revealed compatibility issues with several dependencies that currently lack React 19 support. This can be revisited once the ecosystem catches up.

This migration sets the foundation for future PWA improvements while ensuring stability with the current setup.

Screenhots (if any):

Resolves #

[turingAlan]

@armanalam03 @dinakar17, could you review this PR? I’d appreciate your help. Thanks!

[dinakar17]

Pr is good. But I don't think it's necessary step at the moment. I'll merge it later.

[turingAlan]

Thanks for the input, @dinakar17 ! Since improving the PWA is a key goal, this migration to Next.js 15 is a first step with its native support. Happy to pause if you think other priorities come first—just let me know!