That's basically what an LSP is. It's true that it's built on top of the file system, and most IDE users will navigate using the folder hierarchy, but it still stores information about the name, type, and connectedness of the codebase, and allows querying. Your idea about arbitrary tags (feature, environment) would be useful but does not seem to be supported by the spec [^1] yet.
[^1]: https://microsoft.github.io/language-server-protocol/specifi...