Add CompilerPlugin to Platform model and update filters #1623
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Description (for GitHub PR body):
🧩 Summary
This PR introduces the new CompilerPlugin platform type in Scaladex’s data model.
It prepares the backend for indexing and filtering compiler plugin artifacts such as org.typelevel:kind-projector_2.13.16:0.13.3.
🔧 Changes
Added CompilerPlugin case object to the Platform enum (Platform.scala).
Updated Platform.all and filter mappings to include "compiler-plugin".
Adjusted endpoints and JSON schema definitions to recognize the new platform.
No SQL schema updates required — platforms are stored as string values.
🧪 Testing
Verified backend compilation and existing tests pass with sbt test.
Confirmed that all platform-based endpoints serialize/deserialize correctly.
No behavioral changes to existing platforms.
🧭 Next Steps
Follow-up PRs will:
Add indexing logic for compiler plugin artifacts.
Extend UI to display compiler plugins on front/search/project pages.
Add end-to-end tests and documentation.
🧑💻 Related Issue
Part of scalacenter/scaladex#865