account_invoice_show_currency_rate

Purpose

Deliver accurate invoice exchange rates by recalculating them from the posted journal amounts instead of solely relying on system currency tables.

Features

account.move: Recomputes invoice currency rate for posted invoices from journal line amounts so the displayed rate matches the actual transaction exchange.
account.move: Adds state and journal line dependencies to expected currency rate so invoice and expected rates refresh together when lines change.
account.move.line: Recomputes line currency rate for posted moves from the amounts in foreign and company currencies to reflect the effective exchange.
account.move: Displays the currency rate column on invoice journal items for multi-currency users to surface the applied exchange rate.