Fix websocket server proto definitions to include top-level enums (backport #3130)

[mergify]

The websocket server's "protos" request handler was using descriptor->DebugString() which only outputs message definitions, causing top-level enums (like PixelFormatType) to be omitted from the generated proto definitions sent to clients.

This caused protobuf.js clients to fail parsing the definitions because messages referenced enum types that were never defined.

Changes:

• Extract and include all top-level enums from each proto file
• Use fileDescriptor->enum_type_count() to iterate enums
• Add deduplication sets for both files and enums
• Keep using descriptor->DebugString() for messages to avoid including import statements that would break single-file parsing

The generated proto now includes all necessary enum definitions while remaining compatible with protobuf.js single-file parsing.

Fixes missing PixelFormatType, SphericalCoordinatesType, and other top-level enums in the websocket proto definitions.

Summary

• ✅ Fixes missing top-level enums (PixelFormatType, etc.)
• ✅ Makes proto definitions parseable by protobuf.js
• ✅ Maintains backward compatibility
• ✅ No breaking changes

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by and Generated-by messages.

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This is an automatic backport of pull request #3130 done by [Mergify](https://mergify.com).