Adds محصّل vs إجمالي الإيرادات with a progress bar and remaining balance.
Collection is computed as a pro-rata share of invoice.paid_amount based on
the product line's fraction of the invoice total — so mixed invoices
(product + program) correctly attribute only the product's share of each
payment. Price overrides are excluded from the product's line because they
always land on the program item, leaving the product total_amount intact.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>