## Code Review

This pull request introduces a new library builder for Angular, enabling the compilation, bundling, and packaging of libraries in accordance with the Angular Package Format (APF). The changes include the core builder logic, a dependency graph scanner for entry points, an incremental compilation pipeline, and support for secondary entry points. My review highlights performance optimizations for the dependency predicate and file change detection logic, which are critical for maintaining build speed in larger projects.

## Code Review

This pull request introduces a new library builder (`@angular/build:library`) designed to compile, bundle, and package Angular libraries in compliance with the Angular Package Format (APF). It includes features such as incremental compilation, watch mode, asset copying, secondary entry point resolution, and package.json generation. The review feedback highlights a few critical areas for improvement: ensuring the package name is updated in options when `package.json` changes in watch mode, optimizing startup by avoiding redundant reads of `package.json`, and capturing and propagating stylesheet compilation warnings to the user.

## Code Review

This pull request introduces a new `@angular/build:library` builder designed to compile, bundle, and package Angular libraries in compliance with the Angular Package Format (APF). It features topological sorting of entry points, Rolldown-based ESM and DTS bundling, and a worker pool for concurrent compilation. Feedback on the changes highlights a few critical issues: runtime `ReferenceError`s due to the use of `require` and `require.resolve` in an ESM environment, which should be resolved using `createRequire`; potential overwriting of custom user `.npmignore` files during package.json generation; and a typo in the `AngularCompilationOptions` interface where `declerationMap` should be corrected to `declarationMap`.