refactor: convert to bun workspaces monorepo

- Move web app into apps/web/
- Create packages/shared/ with shared types
- Create plugins/decky-vault/ scaffold
- Root package.json manages workspaces only

apps/web/lib/eden.ts

@@ -0,0 +1,11 @@
+import { treaty } from "@elysia/eden"
+import type { App } from "@/lib/api/app"
+
+// Use require() on the server branch to prevent the client bundler from
+// pulling in Elysia and the route module. The typeof window check is the
+// standard Next.js server-vs-client guard.
+export const api =
+  typeof window === "undefined"
+    ? // eslint-disable-next-line @typescript-eslint/no-require-imports
+      treaty((require("@/lib/api/app") as { app: App }).app).api
+    : treaty<App>(process.env.NEXT_PUBLIC_SITE_URL || "http://localhost:3000").api