Bring odoo-go to ~70%: read_group, record rules, admin, sessions

Phase 1: read_group/web_read_group with SQL GROUP BY, aggregates
  (sum/avg/min/max/count/array_agg/sum_currency), date granularity,
  M2O groupby resolution to [id, display_name].

Phase 2: Record rules with domain_force parsing (Python literal parser),
  global AND + group OR merging. Domain operators: child_of, parent_of,
  any, not any compiled to SQL hierarchy/EXISTS queries.

Phase 3: Button dispatch via /web/dataset/call_button, method return
  values interpreted as actions. Payment register wizard
  (account.payment.register) for sale→invoice→pay flow.

Phase 4: ir.filters, ir.default, product fields expanded, SO line
  product_id onchange, ir_model+ir_model_fields DB seeding.

Phase 5: CSV export (/web/export/csv), attachment upload/download
  via ir.attachment, fields_get with aggregator hints.

Admin/System: Session persistence (PostgreSQL-backed), ir.config_parameter
  with get_param/set_param, ir.cron, ir.logging, res.lang, res.config.settings
  with company-related fields, Settings form view. Technical menu with
  Views/Actions/Parameters/Security/Logging sub-menus. User change_password,
  preferences. Password never exposed in UI/API.

Bugfixes: false→nil for varchar/int fields, int32 in toInt64, call_button
  route with trailing slash, create_invoices returns action, search view
  always included, get_formview_action, name_create, ir.http stub.

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

addons/sale/models/sale_order.go

@@ -322,7 +322,34 @@ func initSaleOrder() {
 				`UPDATE sale_order SET invoice_status = 'invoiced' WHERE id = $1`, soID)
 		}
 
-		return invoiceIDs, nil
+		if len(invoiceIDs) == 0 {
+			return false, nil
+		}
+		// Return action to open the created invoice(s)
+		// Mirrors: odoo/addons/sale/models/sale_order.py action_view_invoice()
+		if len(invoiceIDs) == 1 {
+			return map[string]interface{}{
+				"type":      "ir.actions.act_window",
+				"res_model": "account.move",
+				"res_id":    invoiceIDs[0],
+				"view_mode": "form",
+				"views":     [][]interface{}{{nil, "form"}},
+				"target":    "current",
+			}, nil
+		}
+		// Multiple invoices → list view
+		ids := make([]interface{}, len(invoiceIDs))
+		for i, id := range invoiceIDs {
+			ids[i] = id
+		}
+		return map[string]interface{}{
+			"type":      "ir.actions.act_window",
+			"res_model": "account.move",
+			"view_mode": "list,form",
+			"views":     [][]interface{}{{nil, "list"}, {nil, "form"}},
+			"domain":    []interface{}{[]interface{}{"id", "in", ids}},
+			"target":    "current",
+		}, nil
 	})
 
 	// action_create_delivery: Generate a stock picking (delivery) from a confirmed sale order.
@@ -437,6 +464,54 @@ func initSaleOrderLine() {
 		Order:       "order_id, sequence, id",
 	})
 
+	// -- Onchange: product_id → name + price_unit --
+	// Mirrors: odoo/addons/sale/models/sale_order_line.py _compute_name(), _compute_price_unit()
+	// When the user selects a product on a SO line, automatically fill in the
+	// description from the product name and the unit price from the product list price.
+	m.RegisterOnchange("product_id", func(env *orm.Environment, vals orm.Values) orm.Values {
+		result := make(orm.Values)
+
+		// Extract product_id — may arrive as int64, int32, float64, or map with "id" key
+		var productID int64
+		switch v := vals["product_id"].(type) {
+		case int64:
+			productID = v
+		case int32:
+			productID = int64(v)
+		case float64:
+			productID = int64(v)
+		case map[string]interface{}:
+			if id, ok := v["id"]; ok {
+				switch n := id.(type) {
+				case float64:
+					productID = int64(n)
+				case int64:
+					productID = n
+				}
+			}
+		}
+		if productID <= 0 {
+			return result
+		}
+
+		// Read product name and list price
+		var name string
+		var listPrice float64
+		err := env.Tx().QueryRow(env.Ctx(),
+			`SELECT COALESCE(pt.name, ''), COALESCE(pt.list_price, 0)
+			 FROM product_product pp
+			 JOIN product_template pt ON pt.id = pp.product_tmpl_id
+			 WHERE pp.id = $1`, productID,
+		).Scan(&name, &listPrice)
+		if err != nil {
+			return result
+		}
+
+		result["name"] = name
+		result["price_unit"] = listPrice
+		return result
+	})
+
 	// -- Parent --
 	m.AddFields(
 		orm.Many2one("order_id", "sale.order", orm.FieldOpts{