refactor(Post, PostMapper, PostRepository, CreatePostScreen, HomeScreen): update communityId to channelId for improved clarity

- Renamed communityId to channelId across Post entity, PostMapper, and PostRepository for consistency and clarity.
- Updated CreatePostScreen to include channel selection functionality, enhancing user experience when creating posts.
- Adjusted HomeScreen to support filtering posts by channel, improving content organization.
- Refactored related interfaces and services to align with the new channelId terminology, ensuring a cohesive codebase.

src/data/models/index.ts

@@ -85,7 +85,7 @@ export interface PostModel {
   isFavorited: boolean;
   isTop: boolean;
   status: 'published' | 'draft' | 'deleted';
-  communityId?: string;
+  channelId?: string;
   tags?: string[];
   createdAt: Date;
   updatedAt: Date;