Replaces the free-text description in Landed Cost Taxes and Charges with a
service-item link, drives expense_account from a new Item.default_landed_cost_account,
adds an in-form "Get Items from Vendor Invoices" button, and validates totals
against vendor invoices on submit. Also fixes ERPNext's no-op items_remove
(its `this.trigger` call hits a non-existent method) so applicable_charges
recalculate correctly when rows are deleted from items or taxes.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
