UI Fix: Priority lists do not filter todos on priority

In the second, third and fourth forms in the index.html file, all todos are listed indiscriminately without the priority of the todo objects taken into account.
Steps to solve this issue:
1. Filter todos according to their priority.
2. In the form, Add action and method attributes to the below form. The form makes a post request to delete/id to delete the todo from the Database.
3. Add csrf_token for each form for security.
4. Add title, content, priority, timestamp and a submit button to each of the priority list forms.

Start by inspecting the second, third, and fourth forms in index.html, then trace how todo objects reach those forms and how the delete/id POST request is handled. Verify that each form filters by priority, includes the requested fields and CSRF token, and submits the correct deletion request.

由索引模型根據 Issue 內容生成。