Add evo_megamenu_json extension and seed the megamenu

- new project-neutral extension evo_megamenu_json (Evomedien): a Megamenu
  plugin holding entries, columns, items, teaser cards and a featured slot
  as nested records; presentation settings travel with the payload so the
  front end reads behaviour instead of hard-coding it; published as
  page.10.fields.megaMenu, driven by the site settings megamenu.contentUid
  and megamenu.storagePid
- vitec:seed-megamenu fills one element from the live structure: 5 entries,
  26 columns, 95 items, 4 story cards; items without a page yet are flagged
  pending so the front end falls back to the column link
- vitec:debug-sets prints the resolved site set order
- read-only diagnostics: check_megamenu_schema.php, check_typoscript_templates.php
- docs: schema updates run via extension:setup (database:updateschema no
  longer exists in v14), and a JSON Accept header activates headless-mixed,
  which strips every set-added page field

composer.lock

@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "d902283b2e3364081e0daec494c39cef",
+    "content-hash": "9baf94c6d03b967820c531b235568ece",
     "packages": [
         {
             "name": "apache-solr-for-typo3/solr",
@@ -1424,6 +1424,39 @@
             },
             "time": "2025-08-12T10:13:48+00:00"
         },
+        {
+            "name": "evomedien/evo-megamenu-json",
+            "version": "1.0.0",
+            "dist": {
+                "type": "path",
+                "url": "./packages/evo_megamenu_json",
+                "reference": "d466495bad7206fe59926644544da125747b73c0"
+            },
+            "require": {
+                "typo3/cms-core": "^13.4 || ^14.0"
+            },
+            "suggest": {
+                "friendsoftypo3/headless": "Renders the plugin inside the headless JSON envelope and exposes the menu at page level"
+            },
+            "type": "typo3-cms-extension",
+            "extra": {
+                "typo3/cms": {
+                    "extension-key": "evo_megamenu_json"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Evomedien\\EvoMegamenuJson\\": "Classes"
+                }
+            },
+            "license": [
+                "GPL-2.0-or-later"
+            ],
+            "description": "Editable megamenu for headless TYPO3 - one plugin fills columns, teaser cards and a featured slot, delivered as JSON",
+            "transport-options": {
+                "relative": true
+            }
+        },
         {
             "name": "evomedien/vitec",
             "version": "1.0.1",
@@ -10233,10 +10266,10 @@
     },
     "prefer-stable": false,
     "prefer-lowest": false,
-    "platform": {},
-    "platform-dev": {},
+    "platform": [],
+    "platform-dev": [],
     "platform-overrides": {
         "php": "8.4.0"
     },
-    "plugin-api-version": "2.9.0"
+    "plugin-api-version": "2.3.0"
 }