Revert "Revert rust scm usage (#4277)"

This reverts commit 995aae2.

cli/internal/scm/git_go.go

@@ -1,3 +1,6 @@
+//go:build go || !rust
+// +build go !rust
+
 // Package scm abstracts operations on various tools like git
 // Currently, only git is supported.
 //

cli/internal/scm/git_rust.go

@@ -0,0 +1,28 @@
+// Package scm abstracts operations on various tools like git
+// Currently, only git is supported.
+//
+// Adapted from https://github.com/thought-machine/please/tree/master/src/scm
+// Copyright Thought Machine, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+//go:build rust
+// +build rust
+
+package scm
+
+import (
+	"github.com/vercel/turbo/cli/internal/ffi"
+)
+
+// git implements operations on a git repository.
+type git struct {
+	repoRoot string
+}
+
+// ChangedFiles returns a list of modified files since the given commit, optionally including untracked files.
+func (g *git) ChangedFiles(fromCommit string, toCommit string, monorepoRoot string) ([]string, error) {
+	return ffi.ChangedFiles(g.repoRoot, monorepoRoot, fromCommit, toCommit)
+}
+
+func (g *git) PreviousContent(fromCommit string, filePath string) ([]byte, error) {
+	return ffi.PreviousContent(g.repoRoot, fromCommit, filePath)
+}