fix: rework build validation

[kricsleo]

This PR focus on the build validation:

• Added "shamefully hoisted dependencies" validation
  If a package is directly referenced by the source code (not from nested node_modules) and isn’t listed in any dependency field (dependencies/devDependencies/peerDependencies/optionalDependencies), it will be flagged as a hoisted dependency. Resolves Should we warn about shamefully hoisted dependencies? #527.

• Fixed "unused dependencies" validation
  Previously, this check ran after each build and stopped working due to some previous changes. Now, it runs only after all builds complete since dependencies may be partially used across builds—only then can we determine which are truly unused. Resolves Unused dependencies validation is not working #524.

• Enhanced "missing outputs" validation
  Previously, this check ran after each build. However, entries declared in package.json might be generated incrementally by multiple builds. Now, it runs only after all builds complete. Resolves Passing BuildConfig[] to defineBuildConfig fails on export validation if each BuildConfig iterative populates the ./dist with the exported files. #356.

• Refactored the "implicit dependencies" warning by consolidating them into a single clearer message and improved warning logs for better readability. Resolves Improve log trace for Potential missing package.json files warning #268.

Preview:

[pi0]

Can you please write an overview of changes 🙏

[kricsleo]

Sure, I've updated the description. Looking forward to your feedback! ❤️