feat(sessions): M5 侧边栏抽屉 + 会话列表（切换/新建/删除）

自研 MiuixDrawer（draggable+Animatable，关闭态不拦截触摸）；DataStore 持久化会话快照/序号映射/当前会话；SessionsViewModel 先快照后刷新；次级会话删除二次确认，主会话禁删。

gradle/libs.versions.toml

@@ -12,6 +12,7 @@ kotlinxSerialization = "1.11.0"
 coroutines = "1.11.0"
 securityCrypto = "1.1.0"
 junit = "4.13.2"
+datastore = "1.2.1"
 
 [libraries]
 androidx-core-ktx = { group = "androidx.core", name = "core-ktx", version.ref = "coreKtx" }
@@ -38,6 +39,7 @@ okhttp-logging = { group = "com.squareup.okhttp3", name = "logging-interceptor",
 kotlinx-serialization-json = { group = "org.jetbrains.kotlinx", name = "kotlinx-serialization-json", version.ref = "kotlinxSerialization" }
 kotlinx-coroutines-android = { group = "org.jetbrains.kotlinx", name = "kotlinx-coroutines-android", version.ref = "coroutines" }
 androidx-security-crypto = { group = "androidx.security", name = "security-crypto", version.ref = "securityCrypto" }
+androidx-datastore-preferences = { group = "androidx.datastore", name = "datastore-preferences", version.ref = "datastore" }
 junit = { group = "junit", name = "junit", version.ref = "junit" }
 
 [plugins]