PRO-8571: fix the astro section template library bug introduced in astro 4.9.0 (#5140)

* PRO-8571: fix the astro section template library bug introduced in astro 4.9.0

* version number correct

* bad typo

Author: boutell

CHANGELOG.md

@@ -12,6 +12,8 @@
 
 ### Fixes
 
+* Specify the content type when calling back to Astro with JSON to render an area. This is required starting in Astro 4.9.0 and up, otherwise the request is blocked by CSRF protection.
+
 ## 4.23.0 (2025-10-30)
 
 ### Adds

modules/@apostrophecms/area/index.js

@@ -376,7 +376,9 @@ module.exports = {
           const response = await fetch(`${self.apos.baseUrl}/api/apos-external-front/render-area`, {
             method: 'POST',
             headers: {
-              'apos-external-front-key': self.apos.externalFrontKey
+              'apos-external-front-key': self.apos.externalFrontKey,
+              // Without this Astro enforces CSRF protection starting in version 4.9.0
+              'content-type': 'application/json'
             },
             body: JSON.stringify({
               area