Add stored form views, SO line compute, invoice line demo data

- Stored form views for CRM lead, purchase order, HR employee, project
- SO line price_subtotal compute (qty * price * (1 - discount/100))
- Invoice lines seeded for demo invoices (product + tax + receivable)
- O2M lines now visible in form views (sale orders + invoices)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

addons/sale/models/sale_order.go

@@ -605,6 +605,26 @@ func initSaleOrderLine() {
 		orm.Integer("sequence", orm.FieldOpts{String: "Sequence", Default: 10}),
 	)
 
+	// -- Computed: _compute_amount (line subtotal/total) --
+	// Computes price_subtotal and price_total from qty, price, discount.
+	// Mirrors: odoo/addons/sale/models/sale_order_line.py SaleOrderLine._compute_amount()
+	computeLineAmount := func(rs *orm.Recordset) (orm.Values, error) {
+		env := rs.Env()
+		lineID := rs.IDs()[0]
+		var qty, price, discount float64
+		env.Tx().QueryRow(env.Ctx(),
+			`SELECT COALESCE(product_uom_qty, 0), COALESCE(price_unit, 0), COALESCE(discount, 0)
+			 FROM sale_order_line WHERE id = $1`, lineID,
+		).Scan(&qty, &price, &discount)
+		subtotal := qty * price * (1 - discount/100)
+		return orm.Values{
+			"price_subtotal": subtotal,
+			"price_total":    subtotal, // TODO: add tax amount for price_total
+		}, nil
+	}
+	m.RegisterCompute("price_subtotal", computeLineAmount)
+	m.RegisterCompute("price_total", computeLineAmount)
+
 	// -- Delivery & Invoicing Quantities --
 	m.AddFields(
 		orm.Float("qty_delivered", orm.FieldOpts{String: "Delivered Quantity"}),