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/app-iced/src/pages/instances/text.rs

@@ -85,6 +85,67 @@ impl Texts {
         self.text(Key::InstancesNarrowNote)
     }
 
+    // ------------------------------------------------------------- 启动参数（M157）
+    pub(super) fn launch_title(self) -> &'static str {
+        self.text(Key::InstancesLaunchTitle)
+    }
+    pub(super) fn launch_jvm(self) -> &'static str {
+        self.text(Key::InstancesLaunchJvm)
+    }
+    pub(super) fn launch_jvm_hint(self) -> &'static str {
+        self.text(Key::InstancesLaunchJvmHint)
+    }
+    pub(super) fn launch_game(self) -> &'static str {
+        self.text(Key::InstancesLaunchGame)
+    }
+    pub(super) fn launch_game_hint(self) -> &'static str {
+        self.text(Key::InstancesLaunchGameHint)
+    }
+    pub(super) fn launch_memory(self) -> &'static str {
+        self.text(Key::InstancesLaunchMemory)
+    }
+    /// 「留空 = 跟随全局默认（{default} MiB）」，`default` 是生效值（三级回落之后）。
+    pub(super) fn launch_memory_hint(self, default_mb: u32) -> String {
+        self.0.render(
+            Key::InstancesLaunchMemoryHint,
+            &[("default", &default_mb.to_string())],
+        )
+    }
+    pub(super) fn launch_java(self) -> &'static str {
+        self.text(Key::InstancesLaunchJava)
+    }
+    pub(super) fn launch_java_hint(self) -> &'static str {
+        self.text(Key::InstancesLaunchJavaHint)
+    }
+    pub(super) fn launch_backend(self) -> &'static str {
+        self.text(Key::InstancesLaunchBackend)
+    }
+    /// 「需游戏版本 26.2 及以上（本实例 1.20.4）」。
+    pub(super) fn launch_backend_gated(self, version: &str) -> String {
+        self.0
+            .render(Key::InstancesLaunchBackendGated, &[("version", version)])
+    }
+    /// 「生效：vulkan」。
+    pub(super) fn launch_effective(self, value: &str) -> String {
+        self.0
+            .render(Key::InstancesLaunchEffective, &[("value", value)])
+    }
+    /// 三态后端的显示名（稳定 id → 文案）；**未知 id 返回 `None`**（调用方原样上屏，不猜）。
+    pub(super) fn backend_label(self, id: &str) -> Option<&'static str> {
+        Some(self.text(match id {
+            "default" => Key::InstancesBackendDefault,
+            "opengl" => Key::InstancesBackendOpengl,
+            "vulkan" => Key::InstancesBackendVulkan,
+            _ => return None,
+        }))
+    }
+    pub(super) fn launch_save(self) -> &'static str {
+        self.text(Key::InstancesLaunchSave)
+    }
+    pub(super) fn launch_reset(self) -> &'static str {
+        self.text(Key::InstancesLaunchReset)
+    }
+
     fn text(self, key: Key) -> &'static str {
         self.0.text(key)
     }