feat(scripts): implement report-status.sh with bats and cucumber tests

POST build status to Gitea REST API. Supports pending, success, failure,
error states. Cross-repo reporting via optional root_commit and root_repo
parameters. Includes mock Gitea API server shared between bats unit tests
and cucumber acceptance tests.

tests/features/step_definitions/common.steps.js

@@ -0,0 +1,28 @@
+const { execSync, spawn } = require('child_process');
+const { Before, After, Given } = require('@cucumber/cucumber');
+const path = require('path');
+
+const PROJECT_ROOT = path.resolve(__dirname, '..', '..', '..');
+const MOCK_SCRIPT = path.join(PROJECT_ROOT, 'tests', 'helpers', 'mock-api.sh');
+
+Before({ tags: '@mock' }, function () {
+  execSync(`bash -c 'source "${MOCK_SCRIPT}" && mock_start'`, {
+    cwd: PROJECT_ROOT,
+    stdio: 'ignore',
+  });
+});
+
+After({ tags: '@mock' }, function () {
+  try {
+    execSync(`bash -c 'source "${MOCK_SCRIPT}" && mock_stop'`, {
+      cwd: PROJECT_ROOT,
+      stdio: 'ignore',
+    });
+  } catch (_) { /* ignore */ }
+});
+
+Given('a project repository exists in Gitea', function () {
+});
+
+Given('a commit has been pushed to the repository', function () {
+});