Allow selecting a non-default Google Calendar when creating events with Aki

Description
Users would like the ability to choose which calendar to use when creating events with Aki, especially when multiple calendars exist under the same Google account. Currently, even when specifying a different calendar, events are always created in the default calendar, forcing users to manually change the calendar afterward.

Use case
Many users manage multiple calendars (e.g., Work, Personal, Shared, Projects) within the same Google account. When creating events through Aki, they need to assign the event to a specific calendar, not always the default one.

Current behavior

• Aki creates the event in the default Google Calendar

• Specifying another calendar does not persist

• User must manually move the event after creation

Expected behavior

• Ability to select the target calendar when creating the event

• Option to set a different default calendar for Aki

• Aki should respect the selected calendar when the user specifies one

Impact
Medium — does not block usage, but creates friction for users who manage multiple calendars and schedule frequently.