Add Java extension support and configure multiple JDK runtimes.
Introduce a wrapped VS Code package that includes JDK 25 in the PATH
to support the Red Hat Java language server.
Switch from using `programs.vscode.userSettings` to a manually managed
`settings.json` file via `home.file`. This allows the settings file to
be writable by external tools like `kilo-code` at runtime while
preserving them across Nix configuration switches by using `force = false`.
Add a new module for Visual Studio Code configuration including
default extensions (nix-ide, markdown-all-in-one, prettier) and
nixd/nixfmt settings. Enable vscode on 14900k, t2mbp, and uConsole
hosts with additional extensions.
Also clean up unfree predicate logic in ideapad configuration.
Olivier