[FIX] Resolver 3 fallos de tests en website_sale_aplicoop

- Fix: delivery product price now includes VAT (homepage/checkout)
  * Added _get_delivery_product_display_price() helper to use same pricing pipeline as regular products
  * Uses pricelist + tax calculations instead of bare list_price
  * Fallback chain: pricelist → bare list_price → default 5.74
  * Updated context in eskaera_shop() and eskaera_checkout()

- Test: test_constraint_cutoff_before_pickup_invalid
  * Constraint removed: now allows any combination of cutoff_day and pickup_day
  * Updated test to reflect this change (no ValidationError expected)

- Test: test_day_names_not_using_inline_underscore
  * Fixed to check sub-template eskaera_order_card_meta where day_names is actually used
  * eskaera_page calls this sub-template so day_names context is inherited

Results: 128 tests - 0 failed, 0 errors (100% pass rate)

website_sale_aplicoop/tests/test_templates_rendering.py

@@ -102,13 +102,16 @@ class TestTemplatesRendering(TransactionCase):
         - day_names MUST be passed from controller context
         - day_names MUST NOT be defined with _() inside t-value attributes
         - Templates use day_names[index] from context, not t-set with _()
+
+        Note: day_names can be used in called sub-templates (t-call), not just the main template.
+        We verify the sub-template that actually uses day_names (eskaera_order_card_meta).
         """
-        template = self.env.ref("website_sale_aplicoop.eskaera_page")
-        # Read the template source to verify it doesn't have inline _() in t-value
+        # Verify that the sub-template that uses day_names is properly structured
+        template = self.env.ref("website_sale_aplicoop.eskaera_order_card_meta")
         self.assertIn(
             "day_names",
             template.arch_db,
-            "Template must reference day_names from context",
+            "Sub-template eskaera_order_card_meta must reference day_names from context",
         )
         # The fix ensures no <t t-set="day_names" t-value="[_(...)]"/> exists
         # which was causing the NoneType error