Remove abandoned javatools_backend and Makefile

[lagergren]

Summary

• Removes the javatools_backend/ directory — an on-hold project to compile XTC into Java source code
• Removes the Makefile — a parallel build system to Gradle that existed primarily to support the backend workflow and had no remaining unique functionality
• 239 files deleted, ~20k lines removed

Motivation

We want to keep the XVM reference implementation repo as clean and focused as possible. The javatools_backend was not integrated into the Gradle build, had no dependencies from anywhere else in the project, and contained no reusable assets (no .x files, no code imported by other modules). The Makefile duplicated what Gradle already handles and was primarily the entry point for the backend experiment.

Removing dead code reduces cognitive overhead for contributors and keeps the repo focused on its core purpose: the XVM reference implementation.

Nothing is lost

This code remains fully available in Git history. To browse, search, or restore it at any time:

# Browse the directory as it was before this PR
git show master:javatools_backend/

# View a specific file
git show master:javatools_backend/src/main/java/org/xvm/XEC.java

# Restore the entire directory to your working tree
git checkout master -- javatools_backend/

# Search the old code for a pattern
git log -p --all -S 'pattern' -- javatools_backend/

You can also browse it on GitHub by navigating to any commit prior to this merge.

Future direction

As the XVM project matures past the alpha phase, other components that are not directly part of the XVM itself may be decoupled and migrated to their own repositories. For example, the lang/ tree (which implements language support bindings — tree-sitter grammars, LSP server, VS Code extension, IntelliJ plugin, Emacs mode) is a natural candidate for its own repo. For now, it remains tightly coupled to the rest of the build to ensure full integration and enable rapid development during the alpha.

Test plan

• Verified no Gradle files, settings, CI configs, or source code outside javatools_backend/ reference it
• Verified .gitignore has no entries specific to the backend
• Grep confirms zero remaining references to javatools_backend in the repo

[ggleyzer]

Go for it