[Soroban] Write integration tests with frontend wallet simulation

[Eniola3321]

Description:
Test the full flow from wallet connection to minting using test wallets.
Acceptance Criteria:

Use soroban test framework
Simulate Freighter wallet calls
Test end-to-end mint + royalty flow

[OSEH-svg]

@OSEH-svg has applied to work on this issue as part of the Stellar Wave Program's 3rd wave.

Hello Maintainer,
I’d love to work on this issue. I'm a software developer with 5 years of experience and I’m confident I can deliver a good solution. Please feel free to assign it to me.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @OSEH-svg to this issue.