test(comments): не-вакуумные тесты audit-swallow + dominant-run; CHANGELOG (#512 ревью)

DO1: тест audit-swallow был вакуумен (log() — fire-and-forget void persist(),
.not.toThrow() зелен независимо от try/catch). Теперь: после failInsert()
шпионим Logger.warn + слушаем unhandledRejection, флашим микро/макротаски,
ассертим warn=1 и 0 floating-rejection. Mutation: убрать try/catch у persist
→ красный.
DO2: dominant-run тест не отличал longest от first (самый длинный ран был и
первым). Перестроено: короткий plain ран впереди, длинный bold — следом →
ассерт bold:true держится только при genuine longest; +тест tie→first.
Mutation: reduce→segments[0] → красный.
DO3: CHANGELOG [Unreleased] — 3 записи по #496.
DO4: убран no-op override insertAttrs.comment (=dominant.markAttrs, а он и есть
attributes['comment'] — сегменты фильтруются по нему; {...attributes,comment:
attributes.comment}={...attributes}); коммент про 'defensive re-assert' исправлен.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/server/src/integrations/audit/database-audit.service.spec.ts

@@ -1,3 +1,4 @@
+import { Logger } from '@nestjs/common';
 import { DatabaseAuditService } from './database-audit.service';
 import { AUDIT_CONTEXT_KEY } from '../../common/middlewares/audit-context.middleware';
 import { AuditEvent, AuditResource } from '../../common/events/audit-events';
@@ -115,13 +116,39 @@ describe('DatabaseAuditService', () => {
     expect(inserted).toHaveLength(0);
   });
 
-  it('a failed insert never throws to the caller (audit is a side-record)', async () => {
-    const { service, failInsert } = makeService(ctx());
-    failInsert();
-    // Must not reject / throw.
-    expect(() => service.log(applyPayload())).not.toThrow();
-    await Promise.resolve();
-    await Promise.resolve();
+  it('a failed insert is swallowed with a warn and floats no rejection (audit is a side-record)', async () => {
+    // This pins the load-bearing swallow inside persist(). Because log() is
+    // fire-and-forget (`void this.persist(...)`), it always returns synchronously
+    // without throwing — so `not.toThrow()` alone would stay green even if the
+    // try/catch were removed. We instead observe the two effects the catch is
+    // responsible for: a warn IS emitted, and NO unhandled rejection floats.
+    // Removing persist()'s try/catch reddens both assertions (warn count 0 + a
+    // captured rejection).
+    const warnSpy = jest
+      .spyOn(Logger.prototype, 'warn')
+      .mockImplementation(() => undefined as any);
+    const rejections: unknown[] = [];
+    const onRejection = (err: unknown) => rejections.push(err);
+    process.on('unhandledRejection', onRejection);
+    try {
+      const { service, failInsert } = makeService(ctx());
+      failInsert();
+      expect(() => service.log(applyPayload())).not.toThrow();
+      // Flush microtasks so the rejected insert settles, then give any floated
+      // rejection a macrotask tick to be reported by the runtime.
+      await Promise.resolve();
+      await Promise.resolve();
+      await new Promise((r) => setImmediate(r));
+
+      expect(warnSpy).toHaveBeenCalledTimes(1);
+      expect(String(warnSpy.mock.calls[0][0])).toContain(
+        'Failed to persist audit event',
+      );
+      expect(rejections).toHaveLength(0);
+    } finally {
+      process.off('unhandledRejection', onRejection);
+      warnSpy.mockRestore();
+    }
   });
 
   it('logWithContext() persists with an explicit (non-request) context', async () => {