test(e2e): add comment, release, star, PR and fork tests (#37800)

Adds Playwright e2e coverage for five high-value workflows, each driven
through semantic locators with API-based setup:

- comment on and close an issue
- publish a release
- star and watch a repository
- create a pull request from the compare page
- fork a repository

Also passes `autoInit: false` in existing tests that only exercise
DB-backed units (issues, reactions, milestones, projects, events),
skipping an unused initial commit to speed up their setup and reduce
parallel git contention.

---
This PR was written with the help of Claude Opus 4.7

---------

Co-authored-by: Claude (Opus 4.7) <noreply@anthropic.com>
Co-authored-by: Nicolas <bircni@icloud.com>

tests/e2e/reactions.test.ts

@@ -5,7 +5,7 @@ import {login, apiCreateRepo, apiCreateIssue, randomString} from './utils.ts';
 test('toggle issue reactions', async ({page, request}) => {
   const repoName = `e2e-reactions-${randomString(8)}`;
   const owner = env.GITEA_TEST_E2E_USER;
-  await apiCreateRepo(request, {name: repoName});
+  await apiCreateRepo(request, {name: repoName, autoInit: false});
   await Promise.all([
     apiCreateIssue(request, {owner, repo: repoName, title: 'Reaction test'}),
     login(page),