[ToDo] Reconstruct frontend and backend code

[William-An]

What is this todo related to?=

1. frontend
2. backend
3. Documentation
4. Optimization

What is the todo?

1. Construct/draft a coding standard for frontend code and backend code
2. Do code review on frontend and backend code
3. Reformat code to reduce redundancy and ensure it is easy to read

   1. 57

   2. 56

   3. 58

4. Add documentation
5. Add extensive test
6. Break backend application scheduler into multiple sub apps?

How urgent is the todo?

Should be completed after first alpha version but before the next one to avoid code stuck together preventing fixing it,

Additional context

拒绝屎山 从我做起