fix(@angular/build): re-analyze exports on package.json change in library builder

[alan-agius4]

PR Checklist

Please check to confirm your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/angular/angular-cli/blob/main/CONTRIBUTING.md#-commit-message-guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Documentation content changes
• Other... Please describe:

What is the current behavior?

When running the library builder in watch mode and updating package.json, newly added, removed, or changed entry points in exports are not detected or re-analyzed.

Issue Number: N/A

What is the new behavior?

When package.json changes in watch mode, the exports field is now re-analyzed to detect any added, removed, or modified entry points. New entry points are registered into watched files and trigger a re-compilation, while removed entry points are pruned from cached bundle results.

Also refactored entry point normalization logic into pipeline/entry-points.ts and added unit test coverage for getEntryPointBundleName, normalizeEntryPoints, haveEntryPointsChanged, and updateWatchedEntryPoints.

Does this PR introduce a breaking change?

• Yes
• No

Other information

[gemini-code-assist]

Code Review

This pull request introduces support for dynamically re-analyzing entry points and recompiling them when package.json is modified during watch mode in the Angular library builder. It refactors entry point normalization into pipeline/entry-points.ts and adds helper functions to track and update watched entry points, accompanied by comprehensive unit and behavior tests. The review feedback highlights two key improvement opportunities: throwing an error if the name field is missing or removed from package.json during watch mode to avoid inconsistent states, and typing options.entryPoints as a mutable Map instead of ReadonlyMap in updateWatchedEntryPoints to ensure type safety upon reassignment.

[alan-agius4]

This PR was merged into the repository. The changes were merged into the following branches:

• main: 76dd17d