Deprecated createEventDispatcher usage in Svelte components

The codebase currently uses `createEventDispatcher` [(example usage here)](https://github.com/ankitects/anki/blob/main/ts/routes/deck-options/SaveButton.svelte#L27), which is deprecated in Svelte 5.

The [Svelte 5 migration guide](https://svelte.dev/docs/svelte/v5-migration-guide#Event-changes-Component-events) recommends using callback props instead of dispatching events. It may be worth refactoring affected components to follow the new pattern and maintain forward compatibility with Svelte 5.

Start with ts/routes/deck-options/SaveButton.svelte and read the Svelte 5 migration guide section on component events. Search the Svelte components for createEventDispatcher, identify the affected usages, and determine how callback props should replace them. Done means the affected components no longer use the deprecated API and their existing event behavior remains intact.

Written by the indexing model from the issue text.