fix: respect countNetWorth flag when calculating net worth totals

[theperu]

🎯 Description

Accounts have a "Counts for the net worth" toggle, but this setting was being ignored when calculating the available liquidity shown in the Graphs page.

The monthly transaction queries already correctly filtered by countNetWorth = 1, but the initial balance (summed from all accounts) did not apply the same filter causing accounts excluded from net worth to still inflate the displayed total.

Closes: N/A

📱 Changes

• Filter accounts by countNetWorth when computing the starting balance in StatisticsProvider

🧪 Testing Instructions

Behaviour

1. Create (or edit) an account and set "Counts for the net worth" to off
2. Navigate to the Graphs page
3. Verify that the net worth graph and total do not include the balance of the excluded account
4. Re-enable the toggle on the same account
5. Verify that the net worth graph and total do include that account's balance again

🔍 Checklist for reviewers

• Code is formatted correctly
• Tests are passing
• New tests are added (if needed)
• Style matches the figma/designer requests
• Tested on:
  • iOS
  • Android

[lucaantonelli]

maybe also add the new account.deletedAt == null ? Just to be sure, even if deleted always set countnetworth to false.

[theperu]

I agree, I won't be able to push the changes for at least a week so if you want to do it yourself and merge be my guest 😁