Implemented the dynamic theme manager and merged the supplied themes.

Included

* Standardised all six theme.json files to manifest version 2:
    * admin
    * common
    * corporate
    * saasland
    * swiss
    * welcome
* Every manifest now uses the same fields and structure.
* Separate active frontend and backend themes.
* One-click theme activation.
* Theme preview in a new browser tab without activating it.
* Theme cards showing:
    * Preview
    * Name
    * Version
    * Author
    * Description
    * Theme type
    * Active status
* Dynamic theme-specific settings.
* Support for:
    * Text
    * URL
    * Colour
    * Textarea
    * Checkbox fields
    * Variants
    * Appearance
    * Accent palettes
* Theme ZIP installation.
* Theme ZIP export.
* Asset optimisation.
* Accessibility validation.
* Safe ZIP path validation.
* Theme inheritance.
* Active themes cannot be uninstalled.
* Parent themes cannot be uninstalled while child themes depend on them.
* Stylist administration routes now require an authenticated, verified user.
* Manifest validation now restricts theme types to:
    * frontend
    * backend
    * common
* Added activation tests for independent frontend and backend theme selection.

The supplied corporate theme was incomplete, so I added the required backend entry view and placeholder asset files while preserving its supplied layout.

resources/themes/admin/theme.json

@@ -1,19 +1,23 @@
 {
+  "manifest_version": 2,
   "name": "Dashboard",
   "slug": "admin",
-  "extends": "common",
   "version": "1.0.0",
   "author": "ABSDEV",
   "description": "Backend-only Laravel Livewire and Flux dashboard theme.",
+  "type": "backend",
+  "extends": "common",
   "entry_view": "dashboard",
   "stylesheet": "css/theme.css",
   "script": "js/app.js",
-  "type": "backend",
+  "preview": "images/preview.webp",
   "views": true,
   "livewire_views": true,
   "supports": {
     "dark_mode": true,
     "animations": false,
+    "privacy": false,
+    "terms": false,
     "auth": false,
     "preview": true,
     "variants": true,
@@ -23,7 +27,6 @@
     "accessibility_validation": true
   },
   "variables": {},
-  "preview": "images/preview.webp",
   "variants": {
     "light": {
       "label": "Light",
@@ -38,6 +41,10 @@
       }
     }
   },
+  "appearances": {},
+  "accents": {},
+  "default_appearance": null,
+  "default_accent": null,
   "settings": {
     "site_title": {
       "type": "text",
@@ -54,5 +61,6 @@
       "label": "Primary colour",
       "default": "#2563eb"
     }
-  }
+  },
+  "seo": {}
 }