fix: prevent overwriting unsaved user edits during async save in executeSave function

バグ: executeSave の await 中にユーザー入力 → save完了後 古い内容でstore上書き → CodeMirror/Monaco エディタ巻き戻り。さらに clearSaveTimer が新タイマー消去 → 新入力も永久に保存されない。

原因コード（修正前）:
await fileRepository.saveFileByPath(projectId, path, content);
savingPaths.delete(path);
clearSaveTimer(path);               // 新タイマー消す
updateAllTabsByPath(path, content, false); // 古いcontentでstore上書き

await 中に v2 入力 → store: v2、タイマー: 新 → save完了 → clearSaveTimer で新タイマー消去、updateAllTabsByPath で store を v1 に戻す → valtio検知 → React re-render → content prop変化 → CodeMirror view.dispatch 即座に全文置換、Monaco model.setValue で巻き戻り。

修正後:
await fileRepository.saveFileByPath(projectId, path, content);
savingPaths.delete(path);

const currentContent = getContentFromPanes(tabState.panes, path);
if (currentContent === undefined || currentContent === content) {
  clearSaveTimer(path);
  updateAllTabsByPath(path, content, false);
}
// 変わってたら何もしない → 新タイマー生存、store維持

save中に入力あり → 何もしない。新タイマーが生存し次のsaveで v2 保存。store上書きなし → re-renderなし → エディタ巻き戻りなし。

Author: Stasshe

src/stores/tabState/contentSync.ts

@@ -103,8 +103,16 @@ async function executeSave(path: string, content: string): Promise<boolean> {
     savingPaths.add(path);
     await fileRepository.saveFileByPath(projectId, path, content);
     savingPaths.delete(path);
-    clearSaveTimer(path);
-    updateAllTabsByPath(path, content, false);
+
+    // Check if the user typed new content during the async save.
+    // If so: do NOT overwrite the store/model (would revert edits) and do NOT
+    // cancel the new debounce timer (it must fire to persist the newer content).
+    const currentContent = getContentFromPanes(tabState.panes, path);
+    if (currentContent === undefined || currentContent === content) {
+      clearSaveTimer(path);
+      updateAllTabsByPath(path, content, false);
+    }
+
     for (const l of saveListeners) l(path, true);
     return true;
   } catch (error) {