Update OpenAPI schema

[dotto-api-schema-updater]

This PR updates the OpenAPI schema from dotto-typespec.

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

[hikaru-0602]

これでいいよね？

[Copilot]

Pull request overview

This PR syncs the repository’s OpenAPI contract and generated Go API bindings with the latest dotto-typespec changes, adding the PersonalCalendarItems endpoint and updating several query parameter shapes.

Changes:

• Updated openapi.yaml (new /v1/personalCalendarItems, new TimetableSlot, and several query params renamed to plural array forms like semesters, grades, etc.).
• Regenerated Go server/types (generated/api.gen.go) to match the updated OpenAPI contract.
• Updated handler-side request conversion to use the new pluralized query params.

Reviewed changes

Copilot reviewed 3 out of 4 changed files in this pull request and generated 1 comment.

File	Description
openapi/openapi.yaml	Updates the API contract (new endpoint, schema changes, query parameter shape changes).
generated/api.gen.go	Regenerates Go types/routes/wrappers to reflect the updated OpenAPI schema.
internal/handler/converter.go	Adapts subject list filtering to renamed/pluralized query params.
internal/handler/personal_calendar_item_list.go	Adds the new strict handler method required by the regenerated interface.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

TimetableItem.slot is described as possibly being null ("時間割に含まれていない場合はnull") but the OpenAPI 3.1 schema does not allow null here (it’s just an object ref via allOf). This is a spec/codegen mismatch (clients/validators will reject null). Update the schema to explicitly allow null (e.g., anyOf with the slot ref and {type: 'null'}) or change the description/behavior to mean “field omitted when not applicable”.

Suggested change

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

[kantacky]

LGTM