chore: update demo template to svelte-5

[manuel3108]

Looks like the only missing component is the sverdle one.

Create new project with the demo template

pnpm sv create ./path --template demo

or if you havn't checked it out locally

pnpx https://pkg.pr.new/sveltejs/cli/sv@58 ./path --template demo

Relates #51

[pkg-pr-new]

Open in Stackblitz

pnpm add https://pkg.pr.new/sveltejs/cli/@svelte-cli/ast-tooling@58

pnpm add https://pkg.pr.new/sveltejs/cli/sv@58

pnpm add https://pkg.pr.new/sveltejs/cli/@svelte-cli/core@58

commit: f19a7fe