Light and Dark theme support

[yube01]

Problem or user workflow

User theme toggle button

Proposed outcome

User can switch to their preferred theme

Public source paths

maybe themeprovider can be added in app file

Acceptance evidence

you can switch the theme and check either it worked or not

Scope and non-goals

just a small changes in the global css file or style file

Contribution intent

I am requesting maintainer feedback only

Confirmations

• I searched existing issues before proposing this change.
• The proposal does not add, reconstruct, or request proprietary production source.