perf(backend): 角色/世界观入库改批量——create_many 一次 flush 落全部行

角色入库端点与 toolbox world_entities 入库端点原逐卡/逐条 create（每行一次
SELECT/flush/refresh，N+1 round-trip）。新增 create_many：世界观用 add_all，
角色用一次 IN 查已有名 + 一次 flush（保持 (project_id,name) upsert 幂等与批内
重名去重、保序返回）。单条 create 薄封装 create_many，行为不变（既有调用方/E2E
复用）。复活并复用 CharacterWriteFields、新增 WorldEntityFields 作批量入参。
补两端点「多行一次落库」测试；既有幂等/冲突 gate 测试与 m5 真 pg E2E 全绿。

apps/api/tests/test_toolbox_endpoints.py

@@ -32,7 +32,7 @@ from ww_core.domain.outline_write_repo import OutlineWriteView
 from ww_core.domain.project_repo import ProjectCreate
 from ww_core.domain.repositories import OutlineView
 from ww_core.domain.rule_repo import RuleWriteView
-from ww_core.domain.world_entity_repo import WorldEntityWriteView
+from ww_core.domain.world_entity_repo import WorldEntityFields, WorldEntityWriteView
 from ww_llm_gateway.types import LlmRequest, LlmResponse, ServedBy, Usage
 from ww_shared import AppError, ErrorCode
 
@@ -75,6 +75,15 @@ class _FakeWorldWriteRepo:
         self.rows.append({"type": type, "name": name, "rules": list(rules)})
         return WorldEntityWriteView(id=uuid.uuid4(), type=type, name=name)
 
+    async def create_many(
+        self, project_id: uuid.UUID, entities: list[WorldEntityFields]
+    ) -> list[WorldEntityWriteView]:
+        # 镜像 Sql：批量插入，保序返回逐条 View。
+        return [
+            await self.create(project_id, type=e.type, name=e.name, rules=list(e.rules))
+            for e in entities
+        ]
+
 
 class _FakeOutlineWriteRepo:
     def __init__(self) -> None:
@@ -569,6 +578,30 @@ async def test_ingest_world_entities_no_conflict_writes_201() -> None:
     assert session.commits == 1
 
 
+@pytest.mark.asyncio
+async def test_ingest_multiple_world_entities_all_land_in_one_batch() -> None:
+    # 批量入库：多条实体一次 create_many 全部落库，created 保序，单次 commit。
+    repo = FakeProjectRepo()
+    pid = await _seed_project(repo)
+    gateway = _SchemaRoutingGateway({ContinuityReview: _no_conflicts()})
+    app, session, world_repo, _ = _make_app(project_repo=repo, gateway=gateway)
+    payload = {
+        "world_entities": [
+            {"type": "力量体系", "name": "吞噬系统", "rules": ["每日上限"]},
+            {"type": "势力", "name": "天机阁", "rules": ["中立"]},
+            {"type": "地点", "name": "无尽海", "rules": []},
+        ]
+    }
+
+    async with _client(app) as client:
+        resp = await client.post(f"/projects/{pid}/skills/golden-finger/ingest", json=payload)
+
+    assert resp.status_code == 201
+    assert resp.json()["created"] == ["吞噬系统", "天机阁", "无尽海"]
+    assert [r["name"] for r in world_repo.rows] == ["吞噬系统", "天机阁", "无尽海"]
+    assert session.commits == 1
+
+
 @pytest.mark.asyncio
 async def test_ingest_world_entities_conflict_blocks_409() -> None:
     repo = FakeProjectRepo()