fix: 补全提交遗漏的 McpAuthService（MCP 认证服务）[skip ci]

cfc-backend/src/main/java/com/etotem/cfc/service/mcp/McpAuthService.java

@@ -0,0 +1,32 @@
+package com.etotem.cfc.service.mcp;
+
+import com.etotem.cfc.config.McpConfig;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.stereotype.Service;
+
+import javax.annotation.Resource;
+
+@Slf4j
+@Service
+public class McpAuthService {
+
+    @Resource
+    private McpConfig mcpConfig;
+
+    public boolean validate(String apiKeyHeader) {
+        if (apiKeyHeader == null || apiKeyHeader.isEmpty()) {
+            log.warn("[MCP] 缺少 Mcp-Api-Key 请求头");
+            return false;
+        }
+        String expected = mcpConfig.getApiKey();
+        if (expected == null || expected.isEmpty()) {
+            log.warn("[MCP] 未配置 mcp.api-key，所有请求被拒绝");
+            return false;
+        }
+        boolean ok = expected.equals(apiKeyHeader);
+        if (!ok) {
+            log.warn("[MCP] Mcp-Api-Key 不匹配");
+        }
+        return ok;
+    }
+}