[REF] product_origin_char: simplify to template-based origin

- Move origin_text field from product.supplierinfo to product.template
- Add related field in product.product for variant access
- Remove dependency on product_main_seller
- Update views to show field near category (editable)
- Rewrite tests for new architecture
- Update all documentation (README, readme/ fragments)
- Bump version to 18.0.2.0.0

product_origin_char/readme/DESCRIPTION.rst

@@ -1,5 +1,4 @@
-This module replaces the structured country/state origin fields from ``product_origin``
-with a flexible free-text field that can be defined per supplier.
+This module adds a simple free-text ``origin_text`` field to products.
 
 **Problem:**
 
@@ -17,18 +16,15 @@ These free-form descriptions don't fit into structured country/state fields.
 
 **Solution:**
 
-This module adds a translatable ``origin_text`` field to ``product.supplierinfo`` that:
+This module adds a simple ``origin_text`` field to ``product.template`` that:
 
 * Allows free-form text to describe product origin
-* Is stored per supplier (different suppliers may have different origin info)
-* Is translatable (can be described differently in each language)
-* Is automatically displayed on the product based on the main vendor
-  (from ``product_main_seller`` module)
+* Is accessible from product variants via related field
+* Works with any product workflow
 
 **Features:**
 
-* Free-text ``Origin`` field in supplier info (Purchase tab of product)
-* Computed ``Origin`` field in product form (shows main vendor's origin)
-* Field is visible in product list view (optional column)
-* Full translation support for multiple languages
-* Compatible with existing supplier management workflows
+* Free-text ``Origin`` field in product form
+* Field visible in product list views (optional column)
+* Variants share the same origin as their template
+* Editable from both template and variant views