refactor(data): add mock API adapters, id utility, and toast feedback

lib/api/posts.ts

@@ -0,0 +1,13 @@
+import { mockPosts } from "@/lib/mock"
+
+export function listPosts() {
+  return mockPosts
+}
+
+export function getPostById(postId: string) {
+  return mockPosts.find((post) => post.id === postId)
+}
+
+export function listPostsByAuthor(userId: string) {
+  return mockPosts.filter((post) => post.author.id === userId)
+}