[ADD] product_origin_char: Free text origin field per supplier

New addon to replace structured country/state fields with flexible
free-text origin descriptions.

Features:
- Translatable origin_text field in product.supplierinfo
- Computed origin field in products based on main_seller_id
- Support for creative supplier origin descriptions
- Full OCA documentation structure
- ES/EU translations included
- 8 unit tests (all passing)

Replaces product_origin for use cases where suppliers use non-standardized
origin descriptions (e.g., 'Valencia, Spain', 'Huerta de...', etc.)

Depends on: product, product_main_seller
Author: Criptomart
Funding: Elika Bilbo

product_origin_char/models/product_product.py

@@ -0,0 +1,30 @@
+# Copyright 2026 Criptomart
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+
+from odoo import api
+from odoo import fields
+from odoo import models
+
+
+class ProductProduct(models.Model):
+    _inherit = "product.product"
+
+    origin_text = fields.Char(
+        string="Origin",
+        compute="_compute_origin_text",
+        store=False,
+        help="Origin text from main vendor's supplierinfo",
+    )
+
+    @api.depends("product_tmpl_id.main_seller_id", "seller_ids.origin_text")
+    def _compute_origin_text(self):
+        for product in self:
+            if product.product_tmpl_id.main_seller_id:
+                # Find the supplierinfo record for the main seller
+                main_seller = product.product_tmpl_id.main_seller_id
+                seller = product.seller_ids.filtered(
+                    lambda s, ms=main_seller: s.partner_id == ms
+                )[:1]
+                product.origin_text = seller.origin_text if seller else False
+            else:
+                product.origin_text = False