feat: Add endpoint and service logic to clear all messages within a conversation.

src/messages/messages.controller.ts

@@ -218,6 +218,21 @@ export class MessagesController {
     return this.messagesService.markMessagesAsRead(conversationId, userId);
   }
 
+  // ==========================================
+  // CLEAR CHAT (delete messages, keep conversation)
+  // ==========================================
+  @Delete('conversations/:id/messages')
+  @HttpCode(HttpStatus.OK)
+  @ApiOperation({ summary: 'Clear all messages in a conversation' })
+  @ApiParam({ name: 'id', description: 'Conversation ID' })
+  @ApiResponse({ status: 200, description: 'Messages cleared' })
+  async clearChat(
+    @Param('id') conversationId: string,
+    @CurrentUser('id') userId: string,
+  ) {
+    return this.messagesService.clearChat(conversationId, userId);
+  }
+
   // ==========================================
   // DELETE CONVERSATION
   // ==========================================