did something

internal/domain/git/binary.go

@@ -253,6 +253,84 @@ func WriteFile(repoPath, branch, filePath, content, authorName, authorEmail, mes
 	return nil
 }
 
+// FileUpload holds a file path and its content for a batch commit.
+type FileUpload struct {
+	Path    string // repo-relative path, e.g. "src/main.go"
+	Content []byte
+}
+
+// WriteManyFiles commits all files in a single commit to branch. Each file path
+// must be a clean relative path — no ".." or absolute paths allowed.
+func WriteManyFiles(repoPath, branch, message, authorName, authorEmail string, files []FileUpload) error {
+	if len(files) == 0 {
+		return errors.New("no files to commit")
+	}
+
+	// Validate all paths before touching the filesystem.
+	for _, f := range files {
+		clean := filepath.Clean(filepath.FromSlash(f.Path))
+		if strings.HasPrefix(clean, "..") || filepath.IsAbs(clean) {
+			return fmt.Errorf("invalid file path: %s", f.Path)
+		}
+	}
+
+	tmpDir, err := os.MkdirTemp("", "fb-upload-*")
+	if err != nil {
+		return fmt.Errorf("mktemp: %w", err)
+	}
+
+	baseEnv := []string{"GIT_TERMINAL_PROMPT=0", "HOME=/tmp"}
+	authorEnv := append(baseEnv,
+		"GIT_AUTHOR_NAME="+authorName,
+		"GIT_AUTHOR_EMAIL="+authorEmail,
+		"GIT_COMMITTER_NAME="+authorName,
+		"GIT_COMMITTER_EMAIL="+authorEmail,
+	)
+
+	addWt := exec.Command("git", "worktree", "add", "--force", tmpDir, branch)
+	addWt.Dir = filepath.Clean(repoPath)
+	addWt.Env = baseEnv
+	if out, err := addWt.CombinedOutput(); err != nil {
+		os.RemoveAll(tmpDir)
+		return fmt.Errorf("worktree add: %w: %s", err, out)
+	}
+
+	defer func() {
+		rmWt := exec.Command("git", "worktree", "remove", "--force", tmpDir)
+		rmWt.Dir = filepath.Clean(repoPath)
+		rmWt.Env = baseEnv
+		rmWt.Run()
+		os.RemoveAll(tmpDir)
+	}()
+
+	for _, f := range files {
+		clean := filepath.Clean(filepath.FromSlash(f.Path))
+		fullPath := filepath.Join(tmpDir, clean)
+		if err := os.MkdirAll(filepath.Dir(fullPath), 0755); err != nil {
+			return fmt.Errorf("mkdirall %s: %w", clean, err)
+		}
+		if err := os.WriteFile(fullPath, f.Content, 0644); err != nil {
+			return fmt.Errorf("writefile %s: %w", clean, err)
+		}
+	}
+
+	addC := exec.Command("git", "add", ".")
+	addC.Dir = tmpDir
+	addC.Env = authorEnv
+	if out, err := addC.CombinedOutput(); err != nil {
+		return fmt.Errorf("git add: %w: %s", err, out)
+	}
+
+	commitC := exec.Command("git", "commit", "-m", message)
+	commitC.Dir = tmpDir
+	commitC.Env = authorEnv
+	if out, err := commitC.CombinedOutput(); err != nil {
+		return fmt.Errorf("git commit: %w: %s", err, out)
+	}
+
+	return nil
+}
+
 type Branch struct {
 	Name string `json:"name"`
 }