chore(svelte-leaves): gitignore .svelte-kit/ for command-palette + sortable-list

These two svelte leaves were missing the local .gitignore every other svelte
leaf carries, so their @sveltejs/package build output (.svelte-kit/__package__/)
was accidentally committed and drifted stale on each rebuild. Add the canonical
`.svelte-kit/` ignore and untrack the artifacts (kept on disk).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011JE6gykywo57CcqUJZTsB9

Author: serpentblade

packages/ui/command-palette/packages/svelte/.gitignore

@@ -0,0 +1 @@
+.svelte-kit/