Fix pending balance double-count, remove unused password modals, and show correct approval status

[dangershony]

Summary

• Bug 5 (Pending Balance): WalletInfo.Balance was using AvailableSats (confirmed + unconfirmed), causing double-counting since PendingBalance displayed unconfirmed separately. Changed to use TotalBalanceSats (confirmed only).
• Bug 6 (Password Popups): Removed 3 unnecessary password modal prompts in claim flow, release funds flow, and view private keys — the design app uses SimplePasswordProvider which always returns "default-key".
• Bug 7 (Approval Status Text): SuccessTitle() always returned "Pending Approval" regardless of auto-approval threshold. Added isAutoApproved parameter and new SuccessDescription() method. InvestPageViewModel now sets IsAutoApproved based on the actual threshold check result.
• Integration test assertions: Added Step 8b to SendToSelfTest verifying WalletInfo balance accounting invariants, and added SuccessTitle/IsAutoApproved assertions to MultiFundClaimAndRecoverTest.InvestInProjectAsync() for both below-threshold (auto-approved) and above-threshold (pending approval) scenarios.