feat(admin): implement management UI and CRUD APIs for all entities

Add full CRUD operations for Pokemon, Habitats, Items, Recipes, and Configs
Switch package manager from npm to pnpm across the project
Remove static seed data in favor of UI-driven data management

backend/Dockerfile

@@ -2,7 +2,7 @@ FROM node:22-alpine
 
 WORKDIR /app
 COPY package.json ./
-RUN npm install
+RUN corepack enable && pnpm install
 COPY . .
 EXPOSE 3001
-CMD ["npm", "run", "start"]
+CMD ["pnpm", "run", "start"]