Add Fiat Deposit and Withdrawal Functionality with Event Emission

[jobbykings]

• Added custom storage mapping for fiat_balance: Map<(ContractAddress, felt252), u128>.
• Implemented deposit_fiat and withdraw_fiat functions with balance validation.
• Emitted FiatDeposit and FiatWithdrawal events for on-chain traceability.
• Ensured input validation for currency and amount.
• Maintained compatibility with existing Account, Upgradeable, and SRC9 components.

[caxtonacollins]

@jobbykings Please avoid creating multiple PRs
this pr checks are failing.
use the first PR you created, i have point out some changes here: #7

[jobbykings]

@caxtonacollins I have made the corrections sir

[caxtonacollins]

@jobbykings check is failing, fix it

[caxtonacollins]

where are your tests?

[caxtonacollins]

@jobbykings whats the update on this?

[jobbykings]

@caxtonacollins
sir The tests for deposit_fiat and withdraw_fiat are included in tests/test_account.cairo.
They cover:

Successful deposits and withdrawals

Zero-amount validation

Over-withdrawal protection

[caxtonacollins]

Github workflow is failing

[caxtonacollins]

@jobbykings this PR shows no test file..... please check well....
please join the sync telegram so that we can stay connected: https://t.me/+lcd-x7E_9p4zYTM0

[jobbykings]

@caxtonacollins sir I've now added the missing test file test_account.cairo under the tests/ directory. It was previously untracked due to its original path (contracts/account/tests/), but I’ve moved it, committed the change, and pushed it to the feature/fiat-deposit-withdraw branch.

[jobbykings]

@caxtonacollins sir Hi, I realized the initial PR was missing the test file due to a path issue. I've fixed that and moved the test to the correct tests/test_account.cairo location.

I'm closing this PR and will open a new one with all changes properly tracked. Thank you!