[REM] website_sale_aplicoop: remove dead code and orphaned tests

Duplicate _translate_labels fallback, unreachable /eskaera/add-to-cart and
/eskaera/save-cart routes (the frontend cart is localStorage-only and uses
save-order), redundant pickup wrappers, unused pagination/count helpers and
fields, deprecated JS shims, and the already-empty checkout_summary.js and
i18n key/init leftovers.

Also drops 11 tests/*.py never wired into tests/__init__.py: three were
unimplemented placeholders (setUp with no assertions), and the other eight
had real assertions but were bit-rotted against the current schema (e.g.
res.partner.is_supplier no longer exists) — wiring them in surfaced 43
failures unrelated to this cleanup. Verified 0 failed/0 errors of 270 tests
both before and after.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

website_sale_aplicoop/models/res_config_settings.py

@@ -34,15 +34,3 @@ class ResConfigSettings(models.TransientModel):
         help="Products with stock below or equal to this value will show 'Low Stock' ribbon. "
         "Products with stock = 0 will show 'Out of Stock' ribbon and cannot be added to cart.",
     )
-
-    @staticmethod
-    def _get_products_per_page_selection(records):
-        """Return default page sizes."""
-        return [
-            (5, "5"),
-            (10, "10"),
-            (15, "15"),
-            (20, "20"),
-            (30, "30"),
-            (50, "50"),
-        ]