feat(Bank Transaction): auto-book included bank fees

[barredterra]

Summary

Auto-book included bank fees on Bank Transaction submit (withdrawals) and at reconciliation time (deposits).

Withdrawals: On submit, a Journal Entry is created (Dr Bank Fees / Cr Bank) and allocated against the Bank Transaction, partially reconciling the fee portion.

Deposits: Fee booking is deferred to reconciliation, where the correct counter-account (e.g. receivable) is known. The reconciliation tool matches deposits using deposit + included_fee as the target amount, so the right vouchers are found. At reconciliation:

• Single-currency: A Journal Entry settles both the fee and the invoice in one entry (Dr Bank, Dr Bank Fees / Cr Receivable)
• Multi-currency: A Payment Entry is created with a deduction row for the fee. The system exchange rate determines exchange gain/loss separately from the fee.

Configuration

• New Bank Fee Account field on Bank Account (Link to Expense account, same currency)
• New Enable Automatic Journal Entries for Bank Fees checkbox in Banking Settings
• All company Bank Accounts must have a fee account before the feature can be enabled

Depends on

• feat(Journal Entry Account): add Bank Transaction as Reference Type frappe/erpnext#52760 (min ERPNext version bump)
• fix(accounts): keep zero-net bank transactions with included fees unreconciled frappe/erpnext#54269 (unallocated_amount for deposit=0 + included_fee transactions)

Test plan

• Submit withdrawal with included fee → fee JE created and allocated
• Submit deposit with included fee → no fee JE created
• Reconcile single-currency deposit with fee against Sales Invoice → JE with bank + fee rows, invoice fully cleared
• Reconcile multi-currency deposit with fee against foreign invoice → PE with fee deduction, exchange gain/loss handled separately
• Feature disabled → no fee JE on submit, no fee handling at reconciliation
• Bank Account without fee account rejects save when feature is enabled
• Currency mismatch between bank account and fee account is rejected
• Cancel Bank Transaction → linked fee JEs are cancelled
• Fee larger than withdrawal is rejected

[barredterra]

@greptileai

[greptile-apps]

Fee double-booked on sequential partial reconciliation

get_deposit_included_fee always returns the full bt.included_fee regardless of how many times the deposit has already been partially reconciled. If a user reconciles a deposit of 75 with included_fee=5 against two invoices in separate steps, the fee account is debited twice (2×5=10 instead of 5), and the BT can never be fully reconciled because 5 remains permanently unallocated.

Concretely: step 1 creates JE Dr Bank 45 / Dr Fee 5 / Cr SI1 50, allocating 45 against the BT (unallocated→30). Step 2 again sees included_fee=5, creates JE Dr Bank 25 / Dr Fee 5 / Cr SI2 30, allocating 25 (unallocated→5). The BT remains 5 short and the fee expense is overstated by 5.

A guard is needed before returning included_fee to check whether a fee JE was already booked for this BT — for example by checking whether a JE already exists where is_system_generated=1 and JEA.reference_name = bt.name AND has a bank_fee_account row, or alternatively by only returning the fee when bt.unallocated_amount == bt.deposit (i.e., the first reconciliation step).