Remove unnecessary base64 encoding of localStorage ke

[avinxshKD]

this is not really a bug but the localStorage keys are all being base64 encoded for no reason:

ALL_GRAPHS: window.btoa('ALL_GRAPHS'),
AUTHOR_NAME: window.btoa('AUTHOR_NAME'),

Then decoded every time with window.atob(). This isn't providing any security (localStorage is still wide open in devtools) and it just makes debugging annoying since all the keys look like gibberish.

If the goal was to avoid collisions with other apps, a simple prefix like concore_ would be clearer and faster. Or just drop the encoding entirely since it's adding overhead for no benefit.

[avinxshKD]

hey @pradeeban for this, we need to either:

Migrate existing keys on app load (read old base64 keys, write to new plain keys) or Check both old and new key formats

let me know what do you think, im ready to raise a PR if this makes sense