Support monorepo layout as alternative to multi-repo

[nakurian]

Problem

The framework assumes each service is in its own repo/directory. Many teams use monorepos where all services live under one repository:

my-monorepo/
├── packages/
│   ├── web-ui/
│   ├── bff-gateway/
│   └── order-service/
├── shared/
│   └── common-types/
└── package.json          # workspace root (pnpm/yarn/npm workspaces)

Proposed solution

Add layout option to manifest:

project:
  layout: "monorepo"          # multi-repo (default) | monorepo
  monorepo_root: "../my-app"  # where the monorepo lives
  packages_dir: "packages"    # subdirectory for services

When layout: monorepo:

• Builder creates services under <monorepo_root>/<packages_dir>/<service-name>/
• Shared workspace config (tsconfig, eslint, package.json) generated at root
• shared-lib type services go in a shared/ directory
• Single docker-compose at monorepo root
• Single CI pipeline with per-service change detection