#Ieeesoc Add working dark mode toggle button to website header

[nhxe]

Description

• Added a dark mode toggle button to the website header.
• The toggle updates the theme and persists the user's preference in localStorage.
• This improves accessibility and user experience for those who prefer dark mode.

Breaking Changes

• None.

Additional Information

• No new dependencies added.
• Tested locally; the toggle works and persists the theme across reloads.

[Umang01-hash]

@nhxe Thankyou for your contribution. Would like to request two changes before moving forward:

• Since the feature enhancement is related to website please create a issue here and then let's mention it in the PR.
• Attach a video/screenshot of your changes so that we can see if it is really something that aligns with our design and implementation.
• Alos #Ieeesoc can be changed to GSOC in title.

[Umang01-hash]

@nhxe Are you still working on the issue??

[naveen-bandela-au2]

@nhxe There is no issue ticket associated with this PR. Additionally, whenever working with themes, we need to ensure that the changes are applied to the entire application rather than just a particular component. Therefore, I am closing this PR.