feat(web): 项目级配置 + 会话命名/历史 + 设计文档纳入影响调查

- 会话支持 name/project 字段，上传要件定义后自动命名；前端侧边栏会话历史 + localStorage 恢复，顶部只显示会话名
- 新增 ProjectsStore（SQLite）与 /api/projects CRUD；绑定项目后 _rebuild_source 合并模板/规则/代码库/设计文档，上传区仅要件定义
- StructuredSource.design_docs 与 ImpactReport.design_references；影响调查新增既有设计文档确定性交叉引用（无 LLM）
- 同步更新 docs/design.md §12.7、README、_AI_USAGE_LOG.md；全量测试 558 通过，覆盖率 99.10%

tests/test_impact_agent.py

@@ -3,9 +3,9 @@ import pytest
 
 from genesis.data_models import (
     CellValue, ChangeType, ControllerInfo, EntityInfo, ExcelTable,
-    ExistingSystemInfo, Provenance, ServiceInfo, SheetType, StructuredSource,
+    ExistingSystemInfo, Provenance, RuleDocument, ServiceInfo, SheetType, StructuredSource,
 )
-from genesis.impact.impact_agent import ImpactAgent
+from genesis.impact.impact_agent import ImpactAgent, impact_report_to_dict
 
 
 def _cv(value) -> CellValue:
@@ -201,3 +201,40 @@ def test_impact_report_to_dict_serializable():
     assert d["change_analysis"]["new_elements"][0]["change_type"] == "新規"
     assert d["change_analysis"]["modified_elements"][0]["impacted_existing"] == ["OrderController"]
     assert d["summary"]["modified"] == 1
+
+
+def _doc(name: str, content: str) -> RuleDocument:
+    return RuleDocument(file_name=name, category="design", markdown_content=content,
+                        source_path=name, file_type="word", hash="h")
+
+
+def _ss_with_design(existing, tables, docs) -> StructuredSource:
+    return StructuredSource(tables=tables, template=None, rule_docs=[], image_analyses=[],
+                            existing_system=existing, comments=[], design_docs=docs)
+
+
+def test_design_doc_cross_reference_hits_identifier():
+    docs = [_doc("design_a.docx", "本章描述 OrderController 的限价单处理逻辑与风控。")]
+    tables = [_table("機能一覧", SheetType.FUNCTION, [_row("F001", "新功能", "新規", "")])]
+    report = ImpactAgent().run(_ss_with_design(_existing(), tables, docs), session_id="d")
+    refs = report.design_references
+    ids = {r.identifier for r in refs}
+    assert "OrderController" in ids
+    assert refs[0].doc_name == "design_a.docx"
+    assert "OrderController" in refs[0].snippet
+    # 序列化也包含
+    assert any(r["identifier"] == "OrderController"
+               for r in impact_report_to_dict(report)["design_references"])
+
+
+def test_design_doc_cross_reference_empty_when_no_docs():
+    tables = [_table("機能一覧", SheetType.FUNCTION, [_row("F001", "新功能", "新規", "")])]
+    report = ImpactAgent().run(_ss_with_design(_existing(), tables, []), session_id="d")
+    assert report.design_references == []
+
+
+def test_design_doc_with_empty_content_skipped():
+    docs = [_doc("empty.docx", "")]  # 无正文 → continue（line 164）
+    tables = [_table("機能一覧", SheetType.FUNCTION, [_row("F001", "新功能", "新規", "")])]
+    report = ImpactAgent().run(_ss_with_design(_existing(), tables, docs), session_id="d")
+    assert report.design_references == []  # 无正文设计文档被跳过，line 165 正常执行