[IMP] website_sale_aplicoop: readable slug in the group order URL

Group order pages were published under their database id (`/eskaera/1`), which
says nothing to the member opening the link. `group.order` gains a `slug` field
and the public pages move to `/eskaera/<slug>` (e.g. `/eskaera/escola-fructuos`).

The slug is generated from the order name on creation, is unique, and can be
edited under the name on the form; emptying it regenerates it from the current
name. Values that would make the order unreachable are rejected: a plain number
(the legacy numeric URLs win that match) and the static routes served under
`/eskaera/` (`labels`, `save-order`, `i18n`, ...).

`/eskaera/<id>` and `/eskaera/<id>/checkout` are kept as redirects to their slug
URL, so the links already shared with members keep working. The AJAX endpoints
(`load-page`, `save-order`, `confirm`, ...) stay numeric: they never show up in
the address bar. Consequently the frontend now reads the order id from the
`data-order-id` attribute only, as the URL no longer carries it.

The post-migration script fills the slug of the orders that already existed.

Renaming the `/eskaera` prefix itself (`/escolas` for a schools deployment)
needs no code: a *308 Redirect / Rewrite* rule per public route in Website >
Configuration > Redirects serves the pages on the new prefix, rewrites the
links in the templates and redirects the old URLs, per website. Documented in
`readme/CONFIGURE.rst`.

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

website_sale_aplicoop/migrations/18.0.1.13.0/post-migrate.py

@@ -0,0 +1,30 @@
+"""Backfill the URL slug of consumer group orders created before this version.
+
+Public pages moved from /eskaera/<id> to /eskaera/<slug>. Orders that already
+existed have no slug yet, so they would not be reachable until saved again.
+Generate one from their name, keeping it unique.
+"""
+
+import logging
+
+from odoo import SUPERUSER_ID
+from odoo import api
+
+_logger = logging.getLogger(__name__)
+
+
+def migrate(cr, version):
+    if not version:
+        return
+
+    env = api.Environment(cr, SUPERUSER_ID, {})
+    orders = env["group.order"].search([("slug", "=", False)], order="id")
+    for order in orders:
+        order.slug = order._generate_unique_slug(order.name)
+
+    if orders:
+        _logger.info(
+            "Generated URL slugs for %d consumer group orders: %s",
+            len(orders),
+            ", ".join(orders.mapped("slug")),
+        )