feat(prototype): add upload manager and docker ci

- add prototype upload, list, view, and delete api routes
- add prototype manager ui with search, modal, and theme toggle
- add filesystem-backed zip extraction and serving logic
- switch project to pnpm with updated lockfile and tooling
- add multi-stage dockerfile with standalone next.js output
- add github actions to lint, build, and publish docker images

lib/prototype.ts

@@ -0,0 +1,10 @@
+export interface PrototypeSummary {
+  id: string;
+  name: string;
+  description: string;
+  entryFile: string;
+  createdAt: string;
+  viewUrl: string;
+}
+
+export const THEME_STORAGE_KEY = "prototype-dark-mode";