fix: CKEditor 5 list item ids no longer end up in the content

CKEditor 5 saves a data-list-item-id attribute on every list item, which
it only needs inside the editor; it bloated the frontend HTML and the RTE
content the API and the content feed hand to MyE&P. Both RTE presets now
import ep_theme's Processing.yaml, which removes the attribute on the way
into the database (exitHTMLparser_db); everything else passes unchanged.

Content saved since the go-live is cleaned once by hand after the
deploy (.ddev/plans/sql/2026-10-26-rte-list-item-ids.sql).

Checked locally as an editor: an RTE field with list item ids is stored
without them, other attributes (class on li, data-* on links) stay;
without the change the ids are stored.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

packages/ep_theme/Configuration/RTE/Default.yaml

@@ -1,5 +1,6 @@
 imports:
   - { resource: "EXT:rte_ckeditor/Configuration/RTE/Processing.yaml" }
+  - { resource: "EXT:ep_theme/Configuration/RTE/Processing.yaml" }
   - { resource: "EXT:rte_ckeditor/Configuration/RTE/Editor/Base.yaml" }
   - { resource: "EXT:rte_ckeditor/Configuration/RTE/Editor/Plugins.yaml" }
 

packages/ep_theme/Configuration/RTE/Minimal.yaml

@@ -1,5 +1,6 @@
 imports:
   - { resource: "EXT:rte_ckeditor/Configuration/RTE/Processing.yaml" }
+  - { resource: "EXT:ep_theme/Configuration/RTE/Processing.yaml" }
   - { resource: "EXT:rte_ckeditor/Configuration/RTE/Editor/Base.yaml" }
   - { resource: "EXT:rte_ckeditor/Configuration/RTE/Editor/Plugins.yaml" }
 

packages/ep_theme/Configuration/RTE/Processing.yaml

@@ -0,0 +1,10 @@
+# CKEditor 5 writes a data-list-item-id attribute to every list item it saves; it is only used inside the
+# editor. Removed on the way into the database, everything else passes unchanged.
+processing:
+  exitHTMLparser_db:
+    keepNonMatchedTags: 1
+    tags:
+      li:
+        fixAttrib:
+          data-list-item-id:
+            unset: 1