Add error plugin v1.8.1

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

plugins/error/blueprints.yaml

@@ -0,0 +1,36 @@
+name: Error
+version: 1.8.1
+description: Displays the error page.
+type: plugin
+slug: error
+icon: warning
+author:
+  name: Team Grav
+  email: devs@getgrav.org
+  url: http://getgrav.org
+homepage: https://github.com/getgrav/grav-plugin-error
+keywords: error, plugin, required
+bugs: https://github.com/getgrav/grav-plugin-error/issues
+license: MIT
+dependencies:
+  - { name: grav, version: '>=1.7.0' }
+
+form:
+  validation: strict
+  fields:
+    enabled:
+      type: toggle
+      label: PLUGIN_ADMIN.PLUGIN_STATUS
+      highlight: 1
+      default: 0
+      options:
+        1: PLUGIN_ADMIN.ENABLED
+        0: PLUGIN_ADMIN.DISABLED
+      validate:
+        type: bool
+
+    routes.404:
+      type: text
+      size: medium
+      label: PLUGIN_ERROR.ROUTE_404
+      default: '/error'