fix: 渠道账号群聊同步缓存 key 及成员名称兜底；统一 Docker/Maven 项目约定

backend/.mvn/maven.config

@@ -0,0 +1,2 @@
+--toolchains
+/Users/marsal/Projects/sino-project/sino-mci/backend/.mvn/toolchains.xml

backend/.mvn/toolchains.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<toolchains>
+    <toolchain>
+        <type>jdk</type>
+        <provides>
+            <version>21</version>
+            <vendor>zulu</vendor>
+        </provides>
+        <configuration>
+            <jdkHome>/Library/Java/JavaVirtualMachines/zulu-21.jdk/Contents/Home</jdkHome>
+        </configuration>
+    </toolchain>
+</toolchains>