feat: allow runes in POJO properties

[Ocean-OS]

This is currently an experiment to see how well runes could work as properties in POJOs. This is similar to #11210, but much more seamless. This would enable explicit fine-grained reactivity in objects, without proxying them. Here's an example:

let counter = {
    count: $state(0);
}

This would get compiled to an IIFE, returning something like this:

let counter = (() => {
    let $$1 = $.state(0);
    return {
        get count() {
            return $.get($$1);
        },
        set count($$value) {
            $.set($$1, $$value, true);
        }
    }
})();

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Tests and linting

• Run the tests with pnpm test and lint the project with pnpm lint

[svelte-docs-bot]

Preview: https://svelte-dev-git-preview-svelte-15593-svelte.vercel.app/

[github-actions]

Playground

pnpm add https://pkg.pr.new/svelte@15593

[changeset-bot]

🦋 Changeset detected

Latest commit: 1b0918c

The changes in this PR will be included in the next version bump.

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[Ocean-OS]

I think this references should be working, try to break them to see if there's any issues.

[Ocean-OS]

I apparently forgot how this works in POJOs, so unfortunately this doesn't work anymore, you would have to do something like this instead. It was a nice shortcut, but we probably wouldn't want to confuse people by not following JavaScript's rules.