feat: 重构知识库系统，移除Hermes集成，增强RAG和同步功能

主要变更:
- 移除Hermes智能体及相关回调服务
- 新增知识库RAG、同步、调度、规范化和索引任务服务
- 重构orchestrator服务，增强运行时聊天功能
- 更新前端聊天、政策制度、设置等页面样式和逻辑
- 更新expense_claims和document_intelligence服务
- 删除llm_wiki相关服务和测试文件
- 更新docker-compose配置和启动脚本

start.sh

@@ -198,6 +198,24 @@ probe_server_smoke() {
   return 1
 }
 
+probe_server_port_open() {
+  _probe_python=""
+  _probe_host="$(server_probe_host)"
+  _probe_port="${SERVER_PORT:-8000}"
+
+  if _probe_python="$(server_probe_python)"; then
+    "$_probe_python" -c "import socket, sys; sock = socket.socket(); sock.settimeout(1.5); result = sock.connect_ex((sys.argv[1], int(sys.argv[2]))); sock.close(); raise SystemExit(0 if result == 0 else 1)" "$_probe_host" "$_probe_port" >/dev/null 2>&1
+    return $?
+  fi
+
+  if command -v ss >/dev/null 2>&1; then
+    ss -ltn | grep -q "[.:]${_probe_port}[[:space:]]"
+    return $?
+  fi
+
+  return 1
+}
+
 probe_server_ready() {
   _health_url="${1:-$(server_probe_url)}"
   _smoke_url="${2:-$(server_smoke_url)}"
@@ -271,6 +289,8 @@ start_all() {
     fi
   elif probe_server_health "$probe_url"; then
     error "An existing backend process is responding at $probe_url, but the smoke check failed at $smoke_url. Stop the old FastAPI process and rerun ./start.sh."
+  elif probe_server_port_open; then
+    error "Port ${SERVER_PORT:-8000} is already occupied, but FastAPI health checks are not passing at $probe_url. Stop the stale backend process and rerun ./start.sh."
   else
     info "Starting FastAPI server..."
     (