Update copyright year from 2025 to 2026 on About page

[himanshujays29]

Describe the bug

The About page of the CircuitVerse Interactive Book website displays an outdated copyright year (2025).
Since the project is actively maintained in 2026, this information is no longer accurate.

To Reproduce

Steps to reproduce the behavior:

1. Go to https://learn.circuitverse.org/about.html#about-interactive-book
2. View the "About Interactive Book" section.
3. Observe the text showing Interactive-Book is © 2024 by CircuitVerse.

Expected behavior

The About page should display the updated year:
Interactive-Book is © 2026 by CircuitVerse.

Desktop (please complete the following information):

• OS: Windows 11
• Browser: Chrome
• Version: Latest

Smartphone (please complete the following information):

• Device: N/A
• OS: N/A
• Browser: N/A
• Version: N/A

Additional context

The footer configuration appears to have been updated in recent commits, but the About page
still shows an older year.