fix: serve variant images via custom endpoint instead of product URL

Product image URL was serving placeholder because writing to image_1920
doesn't work for variants (computed field). New approach:
1. Store image in wizard line table (attachment=False, bytea column)
2. Serve directly via /woo/image/{line_id}/{filename} endpoint
3. WC downloads real image data from this URL
4. Also saves to image_variant_1920 for Odoo reference

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

fusion-woo-odoo/fusion_woocommerce/controllers/api.py

@@ -2,11 +2,12 @@
 # Copyright 2026 Nexa Systems Inc.
 # License OPL-1 (Odoo Proprietary License v1.0)
 
+import base64
 import logging
 
 from odoo import http
 from odoo.exceptions import AccessDenied
-from odoo.http import request
+from odoo.http import request, Response
 
 _logger = logging.getLogger(__name__)
 
@@ -14,6 +15,28 @@ _logger = logging.getLogger(__name__)
 class WooApiController(http.Controller):
     """REST endpoints consumed by the WooCommerce WordPress plugin."""
 
+    @http.route('/woo/image/<int:line_id>/<string:filename>',
+                type='http', auth='none', csrf=False, methods=['GET'])
+    def serve_variant_image(self, line_id, filename, **kw):
+        """Serve a variant image from the transient wizard line.
+        Used by WC to download images during variant push."""
+        try:
+            line = request.env['woo.variant.push.line'].sudo().browse(line_id)
+            if not line.exists() or not line.image:
+                return request.not_found()
+            img_data = line.image
+            if isinstance(img_data, str):
+                img_data = base64.b64decode(img_data)
+            elif isinstance(img_data, memoryview):
+                img_data = bytes(img_data)
+            content_type = 'image/png'
+            if filename.lower().endswith('.jpg') or filename.lower().endswith('.jpeg'):
+                content_type = 'image/jpeg'
+            return Response(img_data, content_type=content_type, status=200)
+        except Exception as e:
+            _logger.error("Failed to serve variant image %d: %s", line_id, e)
+            return request.not_found()
+
     def _authenticate_instance(self):
         """
         Validate Bearer token from Authorization header against woo.instance.odoo_api_key.