Mark 7.0 as a LTS release

The schedule is being moved so that LTS releases now happen in May, to align with Django.

CHANGELOG.txt

@@ -1,8 +1,8 @@
 Changelog
 =========
 
-7.0 (xx.xx.xxxx) - IN DEVELOPMENT
-~~~~~~~~~~~~~~~~
+7.0 LTS (xx.xx.xxxx) - IN DEVELOPMENT
+~~~~~~~~~~~~~~~~~~~~
 
  * Add formal support for Django 5.2 (Matt Westcott)
  * Add `WAGTAIL_` prefix to Wagtail-specific tag settings (Aayushman Singh)

docs/releases/7.0.md

@@ -1,4 +1,4 @@
-# Wagtail 7.0 release notes - IN DEVELOPMENT
+# Wagtail 7.0 (LTS) release notes - IN DEVELOPMENT
 
 _Unreleased_
 
@@ -9,6 +9,8 @@ depth: 1
 ---
 ```
 
+Wagtail 7.0 is designated a Long Term Support (LTS) release. Long Term Support releases will continue to receive maintenance updates as necessary to address security and data-loss related issues, up until the next LTS release (typically a period of 12 months).
+
 ## What's new
 
 ### Django 5.2 support