Simplify chat API to use plaintext instead of encrypted fields

src/api/chat.ts

@@ -4,8 +4,7 @@ export interface ChatMessage {
   id: string;
   senderId: string;
   recipientId: string;
-  encryptedContent: string;
-  iv: string;
+  content: string;
   createdAt: string;
 }
 
@@ -39,13 +38,3 @@ export async function deleteMessage(messageId: string) {
   const { data } = await apiClient.delete(`/chat/messages/${messageId}`);
   return data;
 }
-
-export async function getUserPublicKey(userId: string): Promise<{ id: string; chatPublicKey: string | null }> {
-  const { data } = await apiClient.get(`/users/${userId}/public-key`);
-  return data;
-}
-
-export async function updateMyPublicKey(chatPublicKey: string) {
-  const { data } = await apiClient.put('/users/me/public-key', { chatPublicKey });
-  return data;
-}