v0.1.9

Added

• Git.clone — shallow/branched clone with depth read from Legion::Settings.dig(:fleet, :git, :depth)
• Git.fetch — git fetch --all --prune or named remote
• Git.checkout — checkout ref or create new branch with -b
• Worktree.create/remove/list — repo_path: parameter passes chdir: to Open3.capture3 for shared-worker correctness
• Helpers::RepoMaterializer — strategy-based repo materialization (materialize/release); Phase 1 implements :clone strategy with credential_provider injection
• worktree_path now checks Legion::Settings.dig(:fleet, :workspace, :worktree_base) before falling back to :worktree, :base_dir