fix: use correct envVar format and enable platform services

- Fix envVar field names (key/value/description instead of name/default)
- Ghost: use MariaDB platform service instead of SQLite
- WordPress: use MariaDB platform service
- Nextcloud: use MariaDB + Redis platform services
- Gitea: use MariaDB platform service

apps/ghost/versions/1.0.0/config.json

@@ -2,17 +2,15 @@
   "image": "ghost:latest",
   "port": 2368,
   "envVars": [
-    {
-      "name": "database__client",
-      "default": "sqlite3"
-    },
-    {
-      "name": "database__connection__filename",
-      "default": "/var/lib/ghost/content/data/ghost.db"
-    },
-    {
-      "name": "url",
-      "default": "http://localhost:2368"
-    }
-  ]
+    { "key": "database__client", "value": "mysql", "description": "Database client" },
+    { "key": "database__connection__host", "value": "${MARIADB_HOST}", "description": "Database host (auto-injected by platform)" },
+    { "key": "database__connection__port", "value": "${MARIADB_PORT}", "description": "Database port (auto-injected by platform)" },
+    { "key": "database__connection__user", "value": "${MARIADB_USER}", "description": "Database user (auto-injected by platform)" },
+    { "key": "database__connection__password", "value": "${MARIADB_PASSWORD}", "description": "Database password (auto-injected by platform)" },
+    { "key": "database__connection__database", "value": "${MARIADB_DATABASE}", "description": "Database name (auto-injected by platform)" },
+    { "key": "url", "value": "http://localhost:2368", "description": "Public URL of the blog" }
+  ],
+  "platformRequirements": {
+    "mariadb": true
+  }
 }