docs: add the comprehensive money/accounting guide with live screenshots

167-page Arabic guide covering every money-related screen in the
system (139 screens across 20 modules): journal entries, chart of
accounts, all financial statements, checks/bounced checks, bank
reconciliation, treasury, procurement + tenders, purchase orders,
fixed assets, auctions, rentals, sales/POS, payroll/tax/insurance,
membership and sports-activity billing, pricing/discounts, and the
reports catalog. Every screenshot is real, captured logged in as
super admin against the live instance — not mockups.

Building it surfaced and fixed three live bugs along the way (see
previous commit): PO balance/purchase-volume reports referencing
non-existent poi.quantity/qty_received columns, a missing
price-deviation view, and HR insurance form2's wrong join.