chore: remove 13 stale files and clean up project structure

Removed:
- app.py (deprecated Streamlit UI, replaced by api_server.py + frontend/)
- start_agent_jrxml.py (old launcher, replaced by start.py)
- test_reorder.py, e2e_test.py (ad-hoc/outdated test scripts)
- ocr_raw_positions.json (debug output)
- ARCHITECTURE.md, CODE_GUIDE.md, RAG_INTEGRATION.md, ROADMAP.md (superseded by CLAUDE.md)
- EVALUATION_REPORT.md (auto-generated)
- scripts/init_kb.py (replaced by init_default_kb.py)
- validation_service/validate.bat (redundant, start.py covers it)
- sessions/*.json (34 test session files, already gitignored)

Updated:
- CLAUDE.md: removed stale file entries from key mapping table
- README.md: updated init script reference and removed validate.bat
- .gitignore: removed EVALUATION_REPORT.md entry

CLAUDE.md

@@ -98,9 +98,7 @@ validation_service/ (FastAPI, 端口 8001) — 不变
 | `agent/datasource.py` | 数据源模式解析：$P{{xxx}} 参数 vs JDBC 直连 | 低 |
 | `agent/jrxml_windower.py` | JRXML Band 级窗口化引擎：拆解/切分/重组/元素计数校验 | 中 |
 | `validation_service/main.py` | FastAPI 验证服务 | 低 |
-| `scripts/init_kb.py` | 旧 RAG 知识库初始化/模型下载 | 低 |
 | `scripts/init_default_kb.py` | 多租户默认 KB 初始化（默认用户 + 预置 KB） | 低 |
-| `app.py` | ~~旧 Streamlit UI~~（已由 api_server.py + frontend/ 替代） | 废弃 |
 
 ## 关键约定