[ADD] website_sale_disable_cart: extract cart restriction from website_sale_aplicoop

The "shop as a read-only catalog" behaviour lived inside website_sale_aplicoop,
so every site that wanted the eskaera flow also lost the standard cart. It now
ships as its own installable addon, with the redirect target configurable
instead of hardcoded to /eskaera.

- website_sale_disable_cart: hides the cart UI (12 header styles + the product
  card quick-add) and overrides the standard cart endpoints. Redirect URL is
  configurable in Website settings (default /shop); only site-internal paths are
  accepted, so a misconfigured value cannot turn the shop into an open redirect
  nor loop back into a disabled route.
- Fixes carried over from the original code: /shop/cart/quantity is the Odoo 18
  path (it was /shop/cart_quantity, which never matched), the boxed, sidebar and
  sales two/three/four headers were not covered (the cart link stayed visible on
  them), and the routes now override the standard methods instead of registering
  duplicate ones.
- website_sale_aplicoop 18.0.1.12.0: drops the view file and the four redirect
  routes; installing it no longer touches the standard shop.

Upgrade order matters: update website_sale_aplicoop first, then install
website_sale_disable_cart in a second Odoo run — both use the same XPaths and
obsolete records are only cleaned up at the end of a run.

Tests: 8/8 in website_sale_disable_cart, aplicoop unaffected (its 2 failures
predate this change). Verified live on a DB clone: /shop/cart returns 303 to the
configured URL and no cart markup remains on /shop.

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

website_sale_disable_cart/models/__init__.py

@@ -0,0 +1 @@
+from . import res_config_settings  # noqa: F401

website_sale_disable_cart/models/res_config_settings.py

@@ -0,0 +1,18 @@
+# Copyright 2026 Criptomart
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl)
+
+from odoo import fields
+from odoo import models
+
+
+class ResConfigSettings(models.TransientModel):
+    _inherit = "res.config.settings"
+
+    disabled_cart_redirect_url = fields.Char(
+        string="Disabled Cart Redirect URL",
+        config_parameter="website_sale_disable_cart.redirect_url",
+        default="/shop",
+        help="Internal path visitors are sent to when they reach a standard "
+        "cart URL. Must start with '/' and must not point back to /shop/cart; "
+        "otherwise '/shop' is used.",
+    )