test: orchestrator voice sync skip/passthrough 路径覆盖

照 sync_wechat_accounts 的现有测试模式给 WA + 微信 voice 各加 2 个测试：
skip-when-no-root-department（断言 status=skipped + scraper 未调用 + 无 SyncRun）
+ passes-resolved-root-to-scraper（断言 resolved department_id 透传到 scraper）。
顺手补 SyncResult.status 的 'skipped' 第三态文档。

Co-Authored-By: Claude <noreply@anthropic.com>

yunke-server/app/sync/orchestrator.py

@@ -120,8 +120,16 @@ class SyncResult:
     """Outcome of one sync run (one entity / one conversation).
 
     Mirrors the essential fields of the persisted ``SyncRun`` row so callers can
-    react to a run without re-querying the DB. ``status`` is ``"success"`` or
-    ``"failed"``; on failure ``error`` carries the exception text.
+    react to a run without re-querying the DB. ``status`` is one of:
+
+    * ``"success"`` — the scrape + upsert completed (the SyncRun row is
+      persisted with ``status='success'``).
+    * ``"failed"`` — the scrape/upsert raised; ``error`` carries the
+      exception text (the SyncRun row is persisted with ``status='failed'``).
+    * ``"skipped"`` — a precondition was unmet (e.g. no resolvable root
+      ``department_id`` for an endpoint that requires one); ``error`` carries
+      the reason. NO SyncRun row is recorded (a skip is neither success nor
+      failure), so a skipped entity does not advance the watermark.
     """
 
     entity: str