feat: 打通多源新闻记录链路,检索/日报/知识库可见多源 (方案A+B)

- 模型层: EmbeddingResult/SearchResult 新增 sources 字段(主源居首,旧产物兜底)
- M5 run_embedding: events/deduped 产物透传 sources 进 EmbeddingResult
- M6 run_qdrant_ingest: payload 写入 sources(M5 → 回查 M4 → 兜底 [主源])
- vectorstore: 检索读取 payload.sources
- 日报 HTML / CLI search / MCP: 多源显示「财联社 / 新浪 [多源]」
- 新增 scripts/backfill_qdrant_sources.py: 指纹库为权威源,scroll+upsert 回填存量
  (本地模式 set_payload 逐点 0.65s 不可行,改走 ingest 同款快速路径)
- 新增 tests/test_multisource.py 10 个;全量 276 passed

scheduler/reporter.py

@@ -807,7 +807,10 @@ def _render_event_table(events: list[dict], show_source: bool = True,
         imp = ev.get("importance", 0)
         imp_cls = f"imp-{imp}" if imp >= 4 else ""
         title = e["title"][:70]
-        src = _source_name(e.get("source_id", ""))
+        src_ids = e.get("sources") or [e.get("source_id", "")]
+        src = " / ".join(_source_name(s) for s in src_ids if s)
+        if len(src_ids) > 1:
+            src = f'<span title="多源新闻">{src}</span> 📰'
         codes_in_event = {c.strip().split(".")[0] for c in (ev.get("stock_codes") or [])}
         star = "⭐ " if codes_in_event & wl_codes else ""
         code_str = f" <small>({','.join(list(codes_in_event)[:3])})</small>" if codes_in_event else ""