svelte-check failed with 8 type errors: $app/stores' page.params.id
is typed `string | undefined`, and the page passed `id` raw to
helpers that need `string`. Two changes:
- Switch to `$app/state` (the project canonical for new pages — see
routes/albums/[id]/+page.svelte). page.params.id is a direct
property read, not a store subscription. Fall back to "" so id is
always a string; SvelteKit won't actually render the page without
a populated id, but the type-checker doesn't know that.
- Drop the now-unused `writable` import in the test file and update
the mock to expose the new state-shape (object with .params, not a
writable store).
The remaining a11y warnings (tabindex on role=menu/dialog, click
handlers without keyboard events, draggable div without role,
autofocus) are svelte-check warnings — they don't block the build.
Some are pre-existing in FlagPopover; others are tech debt from
slice 1's drag-and-drop and modal patterns. Address as a follow-up
polish task.
bvandeusen
e0a4d13c45