docs(design): 搜索 Agent 装配层设计（app/search/）

方案 A 平铺模块：prompt.py / skills.py / tools.py / vision.py
新增 OCRProvider Protocol + adapters/ocr.py
Prompt 从 TRM4 store/prompts/v2/ 原封不动复制

research-wiki/graph/edges.json

@@ -25,6 +25,16 @@
       "id": "plan:tree-module-vertical-slice",
       "label": "建树模块竖切实现计划",
       "type": "plan"
+    },
+    {
+      "id": "plan:question-gen",
+      "label": "question_gen 模块实现计划",
+      "type": "plan"
+    },
+    {
+      "id": "design:2026-07-07-search-module-design",
+      "label": "搜索 Agent 装配层设计（app/search/）",
+      "type": "design"
     }
   ],
   "links": [
@@ -41,6 +51,13 @@
       "relation": "implements",
       "evidence": "计划逐 Task 实现设计文档中的 11 个模块",
       "added": "2026-07-07T05:27:02.953166+00:00"
+    },
+    {
+      "source": "plan:question-gen",
+      "target": "design:question-gen",
+      "relation": "implements",
+      "evidence": "实现计划覆盖设计文档的全部需求",
+      "added": "2026-07-07T08:32:53.887071+00:00"
     }
   ]
 }