feat(launch): M157 实例级启动参数（五项回落 + graphicsBackend 三态）

core: 新增 game/launch_overrides（LaunchOverrides 五项 All-Option + 三级回落 + 文本补丁校验）与 launch/overrides（拼装落位：全局 java.extra_args 进 user.jvm、实例 jvmArgs 进 override_jvm、gameArgs 进 user.game、memory 进 -Xmx、backend 进 --graphicsBackend 并复用既有版本门槛告警）；实例 schema 登记 launch.* 五键。

presenter: dto/LaunchArgsView+LaunchArgsPatch，主机侧读/写与门槛判定（backend_allowed），AppCommand::SetInstanceLaunchArgs。

cli: 新命令 instances launch-args（读/写/--clear），launch 装配链消费回落值。

app-iced: 实例详情页「启动参数」区（JVM/游戏参数、内存、Java、三态后端 chips + 灰化提示 + 保存/恢复），表单状态归 App、i18n 中英文案同步。

crates/i18n/src/catalog/instances.rs

@@ -78,6 +78,24 @@ macro_rules! instances_entries {
             InstancesStageVerify => ("Verifying", "校验中"),
             InstancesStageLaunch => ("Starting", "启动中"),
             InstancesStageWindow => ("Waiting for window", "等待游戏窗口"),
+            // ── 启动参数区（M157）：实例配置页的五项 + 三态后端 + 门槛提示
+            InstancesLaunchTitle => ("LAUNCH OPTIONS", "启动参数"),
+            InstancesLaunchJvm => ("JVM arguments", "JVM 参数"),
+            InstancesLaunchJvmHint => ("Space separated, quotes allowed. Empty = follow the global extra JVM arguments (both are sent; on duplicates the instance wins).", "空格分隔、支持引号。留空 = 跟随全局附加 JVM 参数（两者叠加下发，同名选项实例赢）。"),
+            InstancesLaunchGame => ("Game arguments", "游戏参数"),
+            InstancesLaunchGameHint => ("Appended last, so they override earlier game arguments. Empty = nothing appended.", "追加在命令行最后，可覆盖前面的游戏参数。留空 = 不追加。"),
+            InstancesLaunchMemory => ("Max memory (MiB)", "最大内存（MiB）"),
+            InstancesLaunchMemoryHint => ("Empty = follow the global default ({default} MiB).", "留空 = 跟随全局默认（{default} MiB）。"),
+            InstancesLaunchJava => ("Java executable", "Java 可执行文件"),
+            InstancesLaunchJavaHint => ("Empty = follow the global setting, then auto-pick (managed > JAVA_HOME > PATH).", "留空 = 跟随全局设置，再退到自动挑选（托管 > 环境变量 > 系统路径）。"),
+            InstancesLaunchBackend => ("Graphics backend", "图形后端"),
+            InstancesLaunchBackendGated => ("Requires MC 26.2+ (this instance: {version}). The flag is not sent on this version.", "需游戏版本 26.2 及以上（本实例 {version}），这个版本不会下发该参数。"),
+            InstancesLaunchEffective => ("Effective: {value}", "生效：{value}"),
+            InstancesBackendDefault => ("Default", "默认"),
+            InstancesBackendOpengl => ("OpenGL", "OpenGL 后端"),
+            InstancesBackendVulkan => ("Vulkan", "Vulkan 后端"),
+            InstancesLaunchSave => ("Save", "保存"),
+            InstancesLaunchReset => ("Reset to global", "恢复跟随全局"),
         } }
     };
 }