…12909)

### Why is this Change Important & Necessary?
<!-- Include any GitHub issue that is fixed/closed using "Fixes
#<number>" or "Closes #<number>" syntax.
Alternately write "Partially addresses #<number>" or "Related to
#<number>" as appropriate. -->

Closes Submitty#12799 

### What is the New Behavior?
Added a Manage Teams section in the Instructor View on Team Gradeables.
Instructors can now see how many teams exist for the gradeable, and have
some options to generate teams for their students:
1. Create Teams from Registration Subsections will group students into
teams based on their registration subsection. Additionally it will set
the team name to be the registration subsection name.
2. Create Single Student Teams will put each student without a team onto
their own, personal team.
3. Delete All Teams will delete every team that hasn't made a submission
yet, except for any team the Instructor-level user is on.

<img width="1920" height="951" alt="Screenshot 2026-06-16 at 16-07-38
Manage Team For manage teams ui - Sample"
src="https://github.com/user-attachments/assets/8d7de462-2a3e-48e2-8008-e9f294fa773f"
/>

### What steps should a reviewer take to reproduce or test the bug or
new feature?
1. checkout the branch and run submitty_install_site :)
2. Create a new team gradeable as instructor. You can see the new
feature by navigating to the create / manage team page from the
gradeables page.
3. Make some registration subsections in the Manage Students page, test
different configurations of subsections across sections, etc.
4. Test the create teams from registration subsections feature and
verify that:
- the numbers on the confirm window make sense, and the numbers on the
manage teams page update accordingly
- teams are properly created from the subsections. if there is a team
size limit, it is ignored and the entire subsection is put on one team.
is this desired?
- Students on a registration subsection that are already on a team
should not be moved to the subsection team
5. Test the Create Single Student teams and verify that each teamless
student is put on their own team
6. Test the Delete All Teams button and verify that teams with
submissions are not deleted, and teams with the instructor on them are
not deleted.

All of these instructor features should work even if the team lock date
has passed. Additionally, if you have any wording / UI suggestions,
please let me know.


### Automated Testing & Documentation
This feature is not covered by e2e tests, which should be made in a
separate PR.

### Other information
If there is some sort of connection to a team that is being deleted, the
database will throw an error as the ajax JSON response (ie frog robot).
Hopefully this never happens, but it does mean the feature is relatively
safe.

---------

Co-authored-by: Nick Ciuica <[email protected]>

### Why is this Change Important & Necessary?
In #12909 I added some features for instructors to manage teams for
their class. These features include: creating teams from subsections,
creating single-student teams, and deleting all teams (without
submissions). However, I did not add Cypress e2e testing for these
features.

### What is the New Behavior?
Cypress e2e testing has been added for the manage teams features.
Creating teams from subsections and single student teams are tested for
the instructor. It will also test that these teams have actually been
created for their users. Then, it will test deleting these teams.

### What steps should a reviewer take to reproduce or test the bug or
new feature?
1. run the spec locally and ensure it passes (both in headless and
headful mode)
2. observe the spec passing on CI
3. Verify that the spec is written with Cypress best practices as this
is the first time I've ever written a cypress test.
Submitty guidelines I followed here:
https://submitty.org/developer/testing/cypress

### Automated Testing & Documentation
It sure is :)

### Other information
This is not a breaking change. 
Luckily, this gradeable (grading team homework pdf) only starts off with
teams with submissions, so the test is free to make and delete teams
without disturbing the initial state of the gradeable (as long as it
makes it to cleanup.)