feat(@angular/build): Support splitting browser and server stats jsonfiles for easier consumption

[tsteuwer-accesso]

This feature supports splitting out the browser and server stats json files so it's easier to inspect the bundle in various analyzers. Today, everything gets dumped into a single file and it's nearly impossible to use without hours of fix -> remove unused browser/server chunks -> analyze and starting the loop all over again.

This feature implements the feature request I made in #28185, along with another developers request to see a stats json file for just the initial page bundle. I've tested this out in my own repository and it's already helped an incredible amount.

Fixes #28185 #28671

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 using --stats-json, the CLI outputs a single stats.json file.

Issue Number: #28185

What is the new behavior?

We now receive a browser-stats.json, server-stats.json, browser-initial-stats.json and server-initial-stats.json

Does this PR introduce a breaking change?

• Yes
• No

This is a breaking change for anyone relying on CI processes that inspect the old stats.json file as it will no longer be named that.

Other information

[tsteuwer-accesso]

@alan-agius4 , made the requested changes. Let me know if there's anything else.

[gemini-code-assist]

Code Review

This pull request refactors the build process to generate separate and filtered stats files for browser and server outputs, replacing the single stats.json with more granular files like browser-stats.json and browser-initial-stats.json. The changes include updates to the application builder, esbuild bundling context, and Webpack configuration. Feedback highlights an opportunity to refactor the metafile filtering logic into a shared utility to reduce code duplication. Additionally, it was noted that the Webpack implementation currently produces a duplicate file for initial stats instead of a filtered one, which should be addressed to ensure feature parity with the esbuild implementation.

[alan-agius4]

Thanks for this. Please see the comments. In addition please rebase and squash your commits.

[tsteuwer-accesso]

Thanks @alan-agius4 , looking into this.

[tsteuwer-accesso]

@alan-agius4 , I've changed this per your review.

When I was creating the unit tests files, I can't import Metafile from esbuild. I kept getting an error stating that No explicit Bazel dependency for this module. Do you know how I can fix this so I don't have to make types for a Metafile or use the hack of Parameters[0] to get the Metafile type?