限制自动切分恢复状态读取大小

在解析 sidecar state 前检查文件大小，避免异常分配。

apps/ai-game-creator-shell/src-tauri/src/ui_editor/commands/separation/persistence.rs

@@ -2,6 +2,8 @@ use super::model::*;
 use crate::ui_editor::commands::separation::*;
 use std::fs;
 use std::path::{Path, PathBuf};
+
+const SEPARATION_STATE_MAX_BYTES: usize = 8 * 1024 * 1024;
 pub fn separation_sidecar_dir(root: &Path, asset_id: &str) -> Result<PathBuf, String> {
     if asset_id.trim().is_empty() || asset_id.trim() != asset_id {
         app_log!("ui_separation.error stage=sidecar_dir reason=invalid_asset_id");
@@ -97,10 +99,31 @@ pub fn read_separation_state(path: &Path) -> Result<SeparationState, String> {
             .and_then(|name| name.to_str())
             .unwrap_or("<unknown>")
     );
+    let metadata = fs::metadata(path).map_err(|error| {
+        app_log!("ui_separation.error stage=state_read reason=metadata error={error}");
+        format!("读取 separation state 信息失败：{error}")
+    })?;
+    if metadata.len() > SEPARATION_STATE_MAX_BYTES as u64 {
+        app_log!(
+            "ui_separation.error stage=state_read reason=too_large bytes={} max_bytes={}",
+            metadata.len(),
+            SEPARATION_STATE_MAX_BYTES
+        );
+        return Err(format!(
+            "separation state 超过 {} 字节上限",
+            SEPARATION_STATE_MAX_BYTES
+        ));
+    }
     let bytes = fs::read(path).map_err(|error| {
         app_log!("ui_separation.error stage=state_read reason=read error={error}");
         format!("读取 separation state 失败：{error}")
     })?;
+    if bytes.len() > SEPARATION_STATE_MAX_BYTES {
+        return Err(format!(
+            "separation state 超过 {} 字节上限",
+            SEPARATION_STATE_MAX_BYTES
+        ));
+    }
     let state: SeparationState = serde_json::from_slice(&bytes).map_err(|error| {
         app_log!("ui_separation.error stage=state_read reason=parse error={error}");
         format!("解析 separation state 失败：{error}")