Centralize Git identity environment construction

internal/antigravity/session.go

@@ -33,8 +33,6 @@ type Options struct {
 	Cwd        string
 	Model      string
 	Resume     string
-	GitName    string
-	GitEmail   string
 	Env        []string
 	Guidance   string
 	Notes      string
@@ -327,13 +325,7 @@ func (s *Session) spawnLocked() error {
 	cmd := procgroup.Command("agy", args...)
 	cmd.Dir = s.opts.Cwd
 	cmd.Stderr = os.Stderr
-	cmd.Env = append(os.Environ(),
-		"GIT_AUTHOR_NAME="+s.opts.GitName,
-		"GIT_AUTHOR_EMAIL="+s.opts.GitEmail,
-		"GIT_COMMITTER_NAME="+s.opts.GitName,
-		"GIT_COMMITTER_EMAIL="+s.opts.GitEmail,
-	)
-	cmd.Env = append(cmd.Env, s.opts.Env...)
+	cmd.Env = append(os.Environ(), s.opts.Env...)
 
 	stdin, err := cmd.StdinPipe()
 	if err != nil {