feat(releaser): add --no-release flag to skip GitLab release creation

Pushes the commit and tag as normal but exits before calling the GitLab
API. Useful when the project is hosted on a non-GitLab forge (e.g.
Gitea) where the release is handled by a separate CI workflow triggered
on the tag push.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

cmd/main_test.go

@@ -460,6 +460,25 @@ func TestRunSkipGitLab(t *testing.T) {
 	}
 }
 
+func TestRunNoRelease(t *testing.T) {
+	_, dir := setupRepoWithRemote(t)
+	addFile(t, dir, "x.go", "// fix")
+	repo, _ := gogit.PlainOpen(dir)
+	w, _ := repo.Worktree()
+	w.Add("x.go")
+	w.Commit("fix: patch something", &gogit.CommitOptions{Author: testSig()})
+
+	// --no-release skips GitLab release even when credentials are configured
+	t.Setenv("CI_SERVER_URL", "https://gitlab.example.com")
+	t.Setenv("CI_PROJECT_ID", "42")
+	t.Setenv("GITLAB_TOKEN", "test-token")
+
+	err := execCmd(t, "--no-release", "--branch", "release/1.2", "--repo", dir)
+	if err != nil {
+		t.Fatalf("--no-release: unexpected error: %v", err)
+	}
+}
+
 func TestRunMissingToken(t *testing.T) {
 	_, dir := setupRepoWithRemote(t)
 	addFile(t, dir, "x.go", "// fix")