feat: add hideOwnBalance option to hide own balance from views

[AkshayRao27]

Adds a "Hide my balance" toggle in Cospend settings → Misc section.

When enabled:

• Your balance row is removed from the settlement view
• Your balance counter is hidden from the navigation sidebar member list

This does not affect the statistics table or any other view.

I'm not a programmer - I asked DeepSeek V4 Flash to study the code and tell me what I'd need for implementing #399 and it suggested the changes here.

I tested this version out in the browser and things seem to work fine. I've also merged these changes into my personal prod branch to check if they play nicely with the cross-project features and the duplicated bills having the current date and things seem fine.

[julien-nc]

Thanks for the PR. You forgot to include the changes to the settings dialog component.
I'm not sure I see the use case for this change. Can you give an example where it's useful?

[AkshayRao27]

You forgot to include the changes to the settings dialog component.

Ah shit, I think messed up... I was working on this and on the cross-project balances thing in parallel and messed the commit structure up. I'll try and disentangle it. I found that bit in my other PR. Sorry, still really new to working with commits and branches and things, so my first few ones aren't very clean.

Can you give an example where it's useful?

This Feature request actually comes from my SO and a couple of my friends xD
Here's a pic of my live instance:

My SO's point here was "seeing my own balance here is entirely redundant especially when I can see my overall balance at the bottom - I want to be able to hide it"

I had two other groups with ~12 and ~6 people in them. A few of my friends from in there were like "there's so much going on in here every little bit of redundant info I can hide will help me visually filter things out better".

Personally, I pretty much ALWAYS leave my own balance in a project hidden, but it's entirely possible that this is a preference thing.

[AkshayRao27]

Rebased and added the missing bits :)