Installs AshGleam into a project. Should be called with mix igniter.install ash_gleam

Configures your Mix project to use MixGleam and AshGleam by applying the changes described in the MixGleam README:

• Adds archives: [mix_gleam: "~> 0.6"] to project/0
• Adds :gleam to the compilers list
• Adds erlc_paths pointing to Gleam build artefacts
• Sets erlc_include_path for Gleam-generated include files
• Sets prune_code_paths: false (required for Elixir >= v1.15.0)
• Adds a deps.get alias that also runs gleam.deps.get
• Adds gleam_stdlib and gleeunit to deps
• Creates a src/ directory for Gleam source files
• Adds build/ to .gitignore