Add AGENTS.md and pnpm build approval for cloud agent development setup

[BenLorantfy]

Summary

Sets up the cloud agent development environment for the nestjs-zod monorepo.

Changes

• AGENTS.md: Added cloud-specific development instructions covering build order, key commands, example app port, and pnpm v10 build approval.
• package.json: Added pnpm.onlyBuiltDependencies to allow @nestjs/core, @scarf/scarf, @swc/core, and esbuild postinstall scripts non-interactively (required for pnpm v10+).

Verified

Check	Status
pnpm install	✅
packages/z build	✅
packages/z tests (22 tests)	✅
packages/nestjs-zod tests (135 tests)	✅
packages/nestjs-zod build	✅
packages/nestjs-zod lint	✅
packages/nestjs-zod format:check	✅
packages/example build + tests	✅
packages/example-dual-zods build + tests	✅
packages/example-esm build	✅
Example app running + Swagger UI	✅
POST /api/people (create Yoda)	✅ 201

Demo

demo_swagger_ui_create_person.mp4

Swagger UI overview
POST 201 response

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