feat(release): add incremental gate and auto CI status for 103 publish

When the runtime artifact is unchanged, carry forward prior gate results and
re-run only REL scenarios; resolve REL-02 from Gitea commit status and allow
stable promotion when canary matches the same artifact bundle.

Co-authored-by: Cursor <cursoragent@cursor.com>

release-gate/release-script.test.mjs

@@ -49,8 +49,10 @@ test('production stable release verifies canary promotion evidence before gate c
   );
   const promotionIndex = source.indexOf('verify-canary-promotion-evidence.mjs');
   const gateIndex = source.indexOf('verify-release-gate-report.mjs');
+  const incrementalIndex = source.indexOf('run-release-gate-incremental.mjs');
   assert.ok(promotionIndex > 0, 'missing canary promotion evidence verifier');
   assert.ok(gateIndex > promotionIndex, 'gate verification must follow promotion evidence');
+  assert.ok(incrementalIndex > 0, 'missing incremental gate fallback');
   assert.doesNotMatch(source, /在同一候选完成 103 灰度验收且晋升证据校验落地前，禁止非 dry-run/);
   assert.match(source, /read_agent_run_status_json/);
   assert.match(source, /sed -n '\/\^\{/);