feat(post): persist new posts and wire like interactions

store/posts.ts

@@ -0,0 +1,48 @@
+import { create } from "zustand"
+import { generateId } from "@/lib/id"
+import { mockPosts } from "@/lib/mock"
+import type { Post, User, UserRole } from "@/lib/types"
+
+interface CreatePostInput {
+  author: User
+  authorRole: UserRole
+  title: string
+  content: string
+  images: string[]
+  tags: string[]
+  linkedOrderId?: string
+  quotedPostId?: string
+}
+
+interface PostState {
+  posts: Post[]
+  createPost: (input: CreatePostInput) => Post
+}
+
+export const usePostStore = create<PostState>((set) => ({
+  posts: mockPosts,
+  createPost: (input) => {
+    const post: Post = {
+      id: generateId("post"),
+      author: input.author,
+      authorRole: input.authorRole,
+      title: input.title.trim(),
+      content: input.content.trim(),
+      images: input.images,
+      tags: input.tags,
+      linkedOrderId: input.linkedOrderId,
+      quotedPostId: input.quotedPostId,
+      likeCount: 0,
+      commentCount: 0,
+      liked: false,
+      pinned: false,
+      createdAt: new Date().toISOString(),
+    }
+
+    set((state) => ({
+      posts: [post, ...state.posts],
+    }))
+
+    return post
+  },
+}))