[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_supplierinfo.py

@@ -0,0 +1,15 @@
+# Copyright 2026 Criptomart
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+
+from odoo import fields
+from odoo import models
+
+
+class ProductSupplierinfo(models.Model):
+    _inherit = "product.supplierinfo"
+
+    origin_text = fields.Char(
+        string="Origin",
+        translate=True,
+        help="Free text to describe product origin (country, region, producer, etc.)",
+    )