Update OpenAPI schema

[dotto-api-schema-updater]

This PR updates the OpenAPI schema from dotto-typespec.

Triggered by: fun-dotto/dotto-typespec@1ed56ee

[Copilot]

Pull request overview

This PR updates the repository’s OpenAPI contract (synced from dotto-typespec) and adjusts the frontend to match API shape changes, notably the move from dayOfWeek/period fields to a nested slot object and the shift from semester to semesters[] query parameters.

Changes:

• Update openapi/openapi.yaml with new endpoints/schemas and pluralized query parameters (e.g., semesters, grades, classes).
• Update timetable UI components to read/write TimetableItem.slot instead of dayOfWeek / period.
• Update server actions to send semesters: [semester] for affected GET endpoints.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/components/timetable/TimetableItemTable.tsx	Read weekday/period from item.slot with a fallback when missing
src/components/timetable/TimetableItemForm.tsx	Submit timetable item creation using { slot: { dayOfWeek, period } }
src/components/timetable/TimetableItemDeleteDialog.tsx	Display deletion description using item.slot
src/app/dotto/timetable/actions.ts	Update timetable list query param from semester to semesters[]
src/app/dotto/course-registrations/actions.ts	Update registrations list query param from semester to semesters[]
openapi/openapi.yaml	Sync OpenAPI changes: new PersonalCalendarItems endpoint, new schemas, and pluralized query params

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[Copilot]

AcademicService.TimetableItem.slot is documented as being null for intensive lectures, but the schema does not allow null (OpenAPI 3.1 uses JSON Schema; allOf: [$ref] alone won’t permit null). Either update the schema to allow null (e.g., anyOf with {type: "null"}) or adjust the description to match the actual contract (e.g., “omitted when not in timetable”).

Suggested change

	allOf:
	- $ref: '#/components/schemas/DottoFoundationV1.TimetableSlot'
	anyOf:
	- $ref: '#/components/schemas/DottoFoundationV1.TimetableSlot'
	- type: 'null'

[Copilot]

This multiline JSX inside AlertDialogDescription will introduce extra whitespace/newlines around the weekday/period and before the closing parenthesis when rendered (HTML collapses newlines into spaces). Consider rendering this as a single continuous string (or explicitly controlling spaces with {" "}) to avoid UI formatting regressions, and avoid repeating the item?.slot conditional twice by computing the label once.