wip: theme system

- Add theme id
- WIP theme cache key
- Force scheme (light/dark) for dynamic theme
- でびるんちゃんかわいい

ui/resources/themes/m3-dynamic_devilun.json

@@ -0,0 +1,11 @@
+{
+  "id": "devilun",
+  "name": "Devilun",
+  "colors": {
+    "primary": "#d1779d",
+    "secondary": "#85a9a5"
+  },
+  "options": {
+    "forceScheme": "dark"
+  }
+}