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- test_reorder.py, e2e_test.py (ad-hoc/outdated test scripts)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- ARCHITECTURE.md, CODE_GUIDE.md, RAG_INTEGRATION.md, ROADMAP.md (superseded by CLAUDE.md)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

scripts/init_kb.py

@@ -1,55 +0,0 @@
-"""初始化 JRXML 向量知识库。
-
-rag_jrxml 子项目独立运行管线（分块→向量化→导入），本脚本仅用于预下载嵌入模型。
-
-用法:
-    python scripts/init_kb.py --download-model   # 预下载嵌入模型
-"""
-
-import os
-import sys
-import argparse
-from pathlib import Path
-
-from dotenv import load_dotenv
-
-sys.path.insert(0, str(Path(__file__).parent.parent))
-load_dotenv()
-
-
-def download_model():
-    """预下载嵌入模型到本地。"""
-    model_name = os.getenv("RAG_EMBED_MODEL", "Qwen/Qwen3-Embedding-0.6B")
-    print(f"正在下载嵌入模型: {model_name}")
-    print("如遇网络超时，可设置环境变量 HF_ENDPOINT=https://hf-mirror.com 使用镜像")
-    print()
-
-    from sentence_transformers import SentenceTransformer
-
-    model = SentenceTransformer(model_name)
-    model.encode("测试下载")
-    print(f"嵌入模型下载完成: {model_name}")
-
-
-def main():
-    parser = argparse.ArgumentParser(description="JRXML 向量知识库工具")
-    parser.add_argument(
-        "--download-model", action="store_true",
-        help="预下载嵌入模型到本地"
-    )
-    args = parser.parse_args()
-
-    if args.download_model:
-        download_model()
-    else:
-        print("用法: python scripts/init_kb.py --download-model")
-        print()
-        print("知识库构建请在 rag/ 子项目中独立运行:")
-        print("  cd rag")
-        print("  python batch_chunker.py jrxml_source")
-        print("  python embed_chunks.py")
-        print("  python import_to_chroma.py")
-
-
-if __name__ == "__main__":
-    main()