fix(deps): 🐛 Bundle core DI dependencies

[haskou]

Summary

• Moves core DI runtime packages node-dependency-injection and fs-extra into package dependencies.
• Removes those packages from optional peers so applications do not need to install them explicitly.
• Declares class-transformer and class-validator as optional Express/routing-controllers peers and updates installation docs.

Validation

• yarn format:check
• yarn lint
• yarn typecheck
• yarn test:coverage (100%)
• yarn docs:build
• yarn --cwd example typecheck
• yarn build
• npx -y depcheck --json

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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