RDS Invite Based Joining Form

Issue Description

After the joining period for RDS has ended, individuals will only be able to access and submit the joining form if they possess an invite code, which must be verified during the form submission process.

Expected Behavior

Inviter should be able to generate the invite code and applicant should be able to join RDS by using that code

Current Behavior

There is no such feature currently

Screenshots

NA

Reproducibility

• This issue is reproducible
• This issue is not reproducible

Steps to Reproduce

Severity/Priority

• Critical
• High
• Medium
• Low

Additional Information

Checklist

• I have read and followed the project's code of conduct.
• I have searched for similar issues before creating this one.
• I have provided all the necessary information to understand and reproduce the issue.
• I am willing to contribute to the resolution of this issue.

Start by locating the existing RDS joining form and its submission API in the backend, then trace how joining periods and applicant access are handled. The work is done when an inviter can generate a code and an applicant can submit the form with a valid code after the joining period ends, while invalid or missing codes are rejected.