Admin track applicants frontend

[ostepan8]

ℹ️ Issue

Closes

📝 Description

added an availability table to the applicant view so admins can see and edit when an applicant is available for each day of the week. the availability data comes from the pandadoc form as free-text and gets displayed as-is in the table.

1. added sundayAvailability field to the application entity since the design includes sunday but it was missing from the model, plus a migration for the new column.
2. created a new PATCH /applications/:appId/availability endpoint with a dto so admins can update individual day availability without touching other fields.
3. built an AvailabilityTable component that matches the figma design
4. created an applicant detail page at /applications/:appId that fetches the application data and renders the availability table.
5. added getApplication and updateAvailability methods to the frontend api client.
6. added sundayAvailability to the seed data so there's test data to work with locally.
7. fixed the discipline table migration to use IF NOT EXISTS for the enum type since it was conflicting with the init migration.
8. registered the Applicant entity in data-source.ts since it was missing and causing the seed to fail.

✔️ Verification

I played around with the functionality and make it look like the design.