[ADD] commission_simple, commission_simple_agent, sale_agent

3 modules backported from v16

sale_agent/models/account_move.py

@@ -0,0 +1,22 @@
+# Copyright 2024-2025 Akretion France (https://www.akretion.com/)
+# @author: Alexis de Lattre <alexis.delattre@akretion.com>
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
+
+from odoo import api, fields, models
+
+
+class AccountMove(models.Model):
+    _inherit = 'account.move'
+
+    invoice_agent_id = fields.Many2one(
+        'res.partner', domain=[('agent', '=', True)], string="Agent",
+        ondelete='restrict', tracking=True,
+        compute='_compute_invoice_agent_id', store=True, readonly=False)
+
+    @api.depends('partner_id', 'move_type')
+    def _compute_invoice_agent_id(self):
+        for move in self:
+            if move.is_sale_document() and move.partner_id:
+                move.invoice_agent_id = move.partner_id.commercial_partner_id.agent_id.id or False
+            else:
+                move.invoice_agent_id = False