github: move artifact and summary logic to dedicated classes

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>

__tests__/github/artifact.test.itg.ts

@@ -0,0 +1,43 @@
+/**
+ * Copyright 2026 actions-toolkit authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {describe, expect, it} from '@jest/globals';
+import fs from 'fs';
+import os from 'os';
+import path from 'path';
+
+import {GitHubArtifact} from '../../src/github/artifact';
+import {Util} from '../../src/util';
+
+const fixturesDir = path.join(__dirname, '..', '.fixtures');
+const tmpDir = fs.mkdtempSync(path.join(process.env.TEMP || os.tmpdir(), 'github-itg-'));
+
+const maybe = !process.env.GITHUB_ACTIONS || (process.env.GITHUB_ACTIONS === 'true' && process.env.ImageOS && process.env.ImageOS.startsWith('ubuntu')) ? describe : describe.skip;
+
+maybe('upload', () => {
+  it('uploads an artifact', async () => {
+    const filename = path.join(tmpDir, `github-repo-${Util.generateRandomString()}.json`);
+    fs.copyFileSync(path.join(fixturesDir, `github-repo.json`), filename);
+    const res = await GitHubArtifact.upload({
+      filename: filename,
+      mimeType: 'application/json',
+      retentionDays: 1
+    });
+    expect(res).toBeDefined();
+    console.log('uploadArtifactResponse', res);
+    expect(res?.url).toBeDefined();
+  });
+});