[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/README_DEV.md

@@ -0,0 +1,114 @@
+# Product Origin Text - Developer Notes
+
+## Technical Implementation
+
+### Architecture
+
+This module extends the product origin information system to use free-text fields instead of structured country/state fields.
+
+**Models:**
+
+1. **product.supplierinfo** - Base model with the `origin_text` field
+   - Field: `origin_text` (Char, translate=True)
+   - This is where the actual data is stored
+   - Each supplier can have a different origin text for the same product
+
+2. **product.template** - Computed field
+   - Field: `origin_text` (Char, computed, store=False)
+   - Computes from main vendor's supplierinfo
+   - Depends on: `main_seller_id`, `variant_seller_ids.origin_text`
+
+3. **product.product** - Computed field (variant level)
+   - Field: `origin_text` (Char, computed, store=False)
+   - Computes from main vendor's supplierinfo
+   - Depends on: `product_tmpl_id.main_seller_id`, `seller_ids.origin_text`
+
+### Why Computed Fields Instead of Related?
+
+The `origin_text` field in `product.template` and `product.product` cannot be a simple `related` field because:
+
+- `main_seller_id` is a `res.partner` record
+- `origin_text` is stored in `product.supplierinfo` records
+- We need to find the supplierinfo record where `partner_id == main_seller_id`
+
+This requires a computed field with custom logic to filter and find the correct supplierinfo record.
+
+### Translation Support
+
+The `origin_text` field in `product.supplierinfo` uses `translate=True`, which means:
+
+- Each language can have a different value
+- Translations are stored in Odoo's translation system
+- When switching languages, the field shows the translated value
+- If no translation exists, it falls back to the default language value
+
+### Store Strategy
+
+The computed fields in product template and product use `store=False` because:
+
+- The value should always reflect the current main vendor
+- If the main vendor changes or its origin text is updated, the product's origin should update automatically
+- No need to store redundant data
+- Reduces database size and update complexity
+
+### Dependencies
+
+- **product** - Core product module
+- **product_main_seller** - Provides `main_seller_id` computed field for products
+
+### Relationship to product_origin
+
+This module is a replacement/alternative to the OCA `product_origin` module:
+
+- `product_origin` provides structured fields (country_id, state_id)
+- `product_origin_char` provides free-text field (origin_text)
+- Both cannot be installed simultaneously without potential conflicts
+- This module was created because suppliers use creative, non-standardized origin descriptions
+
+### Performance Considerations
+
+- Computed fields with `store=False` are calculated on-the-fly
+- Performance is acceptable because the computation is simple (filter + get first)
+- If performance becomes an issue, consider:
+  - Adding `store=True` with proper dependencies
+  - Adding database indexes on frequently searched fields
+  - Caching strategies
+
+### Testing Strategy
+
+Tests cover:
+
+1. **Basic field storage** - Create supplierinfo with origin_text
+2. **Computed field** - Verify product shows main vendor's origin
+3. **Main vendor change** - Verify origin updates when main vendor changes
+4. **Translation** - Verify field is translatable (multilingual support)
+5. **Empty cases** - Product without vendors, vendor without origin
+
+### Future Improvements
+
+Potential enhancements:
+
+- Add migration script from `product_origin` to convert country/state to text
+- Add bulk update wizard to set origin for multiple products
+- Add origin text to purchase order lines
+- Add search/group by origin in product lists
+- Add validation rules (max length, format checks)
+
+## Code Quality
+
+- Follows OCA guidelines
+- Black formatted (line length 88)
+- isort sorted imports
+- Passes flake8 and pylint checks
+- Full test coverage
+- Documented with docstrings
+- Translatable strings handled correctly (no `_()` in field definitions)
+
+## Version History
+
+- **18.0.1.0.0** (2026-02-25) - Initial release
+  - Free-text origin field per supplier
+  - Automatic display based on main vendor
+  - Multi-language support
+  - Full test coverage
+  - OCA documentation structure