refactor(LocalDataSource, PostRepository, ChatScreen): enhance database handling and message loading

- Introduced a promise-based initialization mechanism in LocalDataSource to prevent concurrent initialization issues.
- Updated PostRepository to utilize an enqueueWrite method for database operations, ensuring thread-safe writes.
- Refactored ChatScreen to improve message loading logic, including preloading history and managing scroll behavior more effectively.
- Enhanced message rendering logic to maintain correct indices in inverted lists and optimize user experience during scrolling.

src/data/repositories/PostRepository.ts

@@ -195,10 +195,12 @@ export class PostRepository implements IPostRepository {
   private async saveToLocalCache(post: Post): Promise<void> {
     try {
       await this.localDb.initialize();
-      await this.localDb.run(
-        `INSERT OR REPLACE INTO posts_cache (id, data, updatedAt) VALUES (?, ?, ?)`,
-        [post.id, JSON.stringify(post), new Date().toISOString()]
-      );
+      await this.localDb.enqueueWrite(async () => {
+        await this.localDb.run(
+          `INSERT OR REPLACE INTO posts_cache (id, data, updatedAt) VALUES (?, ?, ?)`,
+          [post.id, JSON.stringify(post), new Date().toISOString()]
+        );
+      });
     } catch (error) {
       console.error('[PostRepository] 保存本地缓存失败:', error);
     }
@@ -210,7 +212,9 @@ export class PostRepository implements IPostRepository {
   private async clearLocalCache(id: string): Promise<void> {
     try {
       await this.localDb.initialize();
-      await this.localDb.run('DELETE FROM posts_cache WHERE id = ?', [id]);
+      await this.localDb.enqueueWrite(async () => {
+        await this.localDb.run('DELETE FROM posts_cache WHERE id = ?', [id]);
+      });
     } catch (error) {
       console.error('[PostRepository] 清除本地缓存失败:', error);
     }
@@ -545,7 +549,9 @@ export class PostRepository implements IPostRepository {
     this.memoryCache.clear();
     try {
       await this.localDb.initialize();
-      await this.localDb.run('DELETE FROM posts_cache');
+      await this.localDb.enqueueWrite(async () => {
+        await this.localDb.run('DELETE FROM posts_cache');
+      });
     } catch (error) {
       console.error('[PostRepository] 清除所有缓存失败:', error);
     }