feat: 敏感词管理页面（脱敏词后台化，限 lqq 账号）

- 后端 /api/sensitive-words：全局共享词表，开放读、admin 或 lqq 整体替换写
- 前端 desensitize 种子化：SEED_DESENSITIZE_MAP + 运行时 replaceDesensitizeMap
- 启动加载后台配置回灌脱敏映射；管理页支持增删改启停 + 一键导入种子词
- 入口置于左下角设置下拉（全量/简洁两种侧边栏均有），仅用户名 lqq 可见

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

offline-backend-20260512/backend/app/gateway/app.py

@@ -63,6 +63,7 @@ from app.gateway.routers import (
     roundtable_jobs,
     runs,
     scheduled_tasks,
+    sensitive_words,
     skills,
     suggestions,
     system_settings,
@@ -1343,6 +1344,9 @@ This gateway provides custom endpoints for models, MCP configuration, skills, an
     # Sidebar-menu overrides (菜单管理) at /api/menu-overrides
     app.include_router(menu_overrides.router)
 
+    # Sensitive-word map (敏感词管理 / 脱敏词) at /api/sensitive-words
+    app.include_router(sensitive_words.router)
+
     # Standalone parallel multi-agent panel: fan-out streaming + saved tasks
     app.include_router(parallel_agents.router)
     app.include_router(parallel_agent_tasks.router)