fix: preserve Nix Ruby in init wrapper

[pcasaretto]

Problem

The Nix/Home Manager install path generated a broken shell function from try init.

try needs to install a shell function because a subprocess cannot cd the parent shell. That function captures try exec output and evals it.

Before this change, the generated function invoked the Ruby script explicitly through the ambient Ruby:

out=$(/usr/bin/env ruby '/nix/store/.../bin/.try-wrapped' exec ...)

For Nix builds, wrapProgram installs:

bin/try          # wrapper that sets PATH to include Nix Ruby
bin/.try-wrapped # actual Ruby script

When try init runs under that wrapper, $0 resolves to the internal .try-wrapped script. The emitted shell function therefore bypasses bin/try, which means it also bypasses the Nix-provided Ruby. On macOS this falls back to the system Ruby, which is too old for the current code and fails at runtime.

In short:

works:  bin/try -> Nix Ruby -> Ruby script
breaks: /usr/bin/env ruby -> .try-wrapped

Fix

This removes the wrapper layer from the Nix package and makes the generated shell function call the resolved executable directly.

Changes:

• try init now emits direct executable calls:

  out=$('/path/to/try' exec ...)

  instead of:

  out=$(/usr/bin/env ruby '/path/to/try' exec ...)

• The Nix derivation no longer uses wrapProgram.

• The Nix derivation patches the installed script shebang to the packaged Ruby:

  #!/nix/store/...-ruby-3.3.x/bin/ruby

As a result, the Nix package contains a single public executable script:

bin/try

There is no .try-wrapped, no package-specific logic in the Ruby code, and the shell integration preserves the executable selected by the installer/package manager.

Tests

nix build .
./spec/tests/runner.sh ./result/bin/try

Result:

388/388 passed