Rewrite cosmetics and theme preferences (#1328)

- Cosmetics and theme preferences are now only stored in cookies instead
  of a combination of both cookies and state.

- The theme plugin now supports client hints. This allows the server
  to render a page using the client-preferred theme provided it supplies
  this information (any browser other than Firefox), helping to avoid an
  annoying flash while the page is hydrating.

- For the future, the theme plugin now supports additional light themes.
  Light theme preferences are currently not stored, but this can easily
  be fixed if the need arises.

- The previous workaround using the Nitro plugin has been removed. Its
  functionality is now handled by the Nuxt theme plugin with cleaner
  code.

- All pages and components now use the new plugins.

- Compared to the previous attempt, this commit has been improved to be
  more robust in cases where the theme cookie contains invalid values.

Co-authored-by: Geometrically <18202329+Geometrically@users.noreply.github.com>

apps/frontend/src/plugins/cosmetics.ts

@@ -0,0 +1,60 @@
+import type { DarkTheme } from "./theme/index.ts";
+
+export type DisplayMode = "list" | "gallery" | "grid";
+
+export type DisplayLocation =
+  | "mod"
+  | "plugin"
+  | "resourcepack"
+  | "modpack"
+  | "shader"
+  | "datapack"
+  | "user"
+  | "collection";
+
+export interface Cosmetics {
+  searchLayout: boolean;
+  projectLayout: boolean;
+  advancedRendering: boolean;
+  externalLinksNewTab: boolean;
+  notUsingBlockers: boolean;
+  hideModrinthAppPromos: boolean;
+  preferredDarkTheme: DarkTheme;
+  searchDisplayMode: Record<DisplayLocation, DisplayMode>;
+  hideStagingBanner: boolean;
+}
+
+export default defineNuxtPlugin({
+  name: "cosmetics",
+  setup() {
+    const cosmetics = useCookie<Cosmetics>("cosmetics", {
+      maxAge: 60 * 60 * 24 * 365 * 10,
+      sameSite: "lax",
+      secure: true,
+      httpOnly: false,
+      path: "/",
+      default: () => ({
+        searchLayout: false,
+        projectLayout: false,
+        advancedRendering: true,
+        externalLinksNewTab: true,
+        notUsingBlockers: false,
+        hideModrinthAppPromos: false,
+        preferredDarkTheme: "dark",
+        searchDisplayMode: {
+          mod: "list",
+          plugin: "list",
+          resourcepack: "gallery",
+          modpack: "list",
+          shader: "gallery",
+          datapack: "list",
+          user: "list",
+          collection: "list",
+        },
+        hideStagingBanner: false,
+      }),
+    });
+
+    return { provide: { cosmetics } };
+  },
+});