feat: add plan table course search and add

[xyspg]

📌 What's Changed
add plan table course search and add. Closes #87

drag and drop support.

CleanShot.2025-11-10.at.02.36.06.mp4

✅ Actions

Known issue:

• there is some problem in degree report parsing, see degree progree report incorrectly parses year #92. So the manual add dialog will mismatch the year and student's acadmic year. will change it to first year / second year, etc.
  

📝 Notes for Reviewer

[chenxin-yan]

regarding #92 , FYI, the First year and graduation year is determined through the date in students record not through parsing. I think that's where the inconsistency come from as the seeding data for student starts at 2023 fall. Good call tho. I will change it so that instead of letting user fill that out during onboarding, it will be inferred from Degree Progress Report. User can later edit the starting and graduation date in user profile page (#83).

[xyspg]

I have finished this PR. But one thing is that some course, for example, CSCI-UA 102 Data Structures only offer in Fall / Spring. but there is no such term info in our db. we should throw an error if user tries to add this course to summer.