feat(config): wire MinerU and material RAG settings

Add MINERU_* / MATERIAL_* to config loader, .env.example, and
compose env passthrough. Secrets stay in local .env only.

Co-authored-by: Cursor <cursoragent@cursor.com>

.env.example

@@ -63,6 +63,15 @@ RERANKER_ENDPOINT_URL=https://www.dmxapi.cn/v1/rerank
 RERANKER_MODEL=bge-reranker-v2-m3-free
 RERANKER_API_KEY=
 
+# --- 9b. MinerU 文档解析（上传 PDF/Office 异步解析；未配置 KEY 时降级本地提取）---
+MINERU_ENDPOINT_URL=https://mineru.net
+MINERU_API_KEY=
+MINERU_MODEL_VERSION=vlm
+MINERU_LANGUAGE=ch
+MINERU_TIMEOUT=90s
+MATERIAL_FULLTEXT_MAX_BYTES=61440
+MATERIAL_RAG_TOP_K=8
+
 # --- 10. 专属业务/上下文库（Go 宿主：CONTEXT_DB_*；compose 同时认 SYSTEM_DB_* 别名）---
 CONTEXT_DB_HOST=127.0.0.1
 CONTEXT_DB_PORT=5433