Room list: edit or remove custom sections (#33283)

* feat(sc): add section menu to section header

* feat(rls): add edit and remove sections

* feat(dialog): add editing mode to CreateSectionDialog

* feat(dialog): add remove section dialog

* feat(vm): wire up vm and stores

* test: update existing snapshots

* test(e2e): add playwright tests to edit and remove a section

* chore: fix remove section i18n key

* fix: able to send empty sections

* chore: update create section editing docs

* chore: remove useless fallback

* chore: add logs when section is unknown

* feat: use different wording when removing an empty section

* fix: only animate the chevron icon in the section header

* fix: change dialog subtitle weight to medium

apps/web/res/css/views/dialogs/_RemoveSectionDialog.pcss

@@ -0,0 +1,10 @@
+/*
+ * Copyright 2026 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only OR LicenseRef-Element-Commercial
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+.mx_RemoveSectionDialog {
+    color: var(--cpd-color-text-primary);
+}