Centralize Git identity environment construction

cmd/byre/run.go

@@ -13,6 +13,7 @@ import (
 	"strings"
 
 	"g.fc.run/ai/byre/internal/claude"
+	"g.fc.run/ai/byre/internal/git"
 )
 
 func runCmd(args []string) {
@@ -27,10 +28,9 @@ func runCmd(args []string) {
 
 	ctx := context.Background()
 	s, err := claude.Start(ctx, claude.Options{
-		Cwd:      dir,
-		Resume:   *resume,
-		GitName:  gitConfig(dir, "user.name"),
-		GitEmail: gitConfig(dir, "user.email"),
+		Cwd:    dir,
+		Resume: *resume,
+		Env:    git.IdentityEnv(gitConfig(dir, "user.name"), gitConfig(dir, "user.email")),
 	})
 	if err != nil {
 		fatal("start claude", "err", err)