Add svelte-5-snippets extension

[polvallverdu]

Adds the svelte-5-snippets extension — a port of the VS Code svelte-5-snippets extension by Chanzhaoyu.

68 snippets across:

• Svelte 5 runes ($state, $derived, $effect, $props, $host — including all sub-APIs)
• Svelte template syntax ({#if}, {#each}, {#await}, {@render}, {#snippet}, transitions, etc.)
• Svelte structural elements (<script>, <style>, <svelte:*> tags)
• SvelteKit scaffolding (load functions, API routes, actions, hooks, env imports)
• CSS (:global())

Checklist:

• Extension ID does not contain "zed" or "extension"
• Uses HTTPS submodule URL
• Submodule commit is on a branch (not detached)
• MIT license included
• pnpm sort-extensions run
• Tested locally via "Install Dev Extension" in Zed

[cla-bot]

We require contributors to sign our Contributor License Agreement, and we don't have @polvallverdu on file. You can sign our CLA at https://zed.dev/cla. Once you've signed, post a comment here that says '@cla-bot check'.

[polvallverdu]

@cla-bot check

[cla-bot]

The cla-bot has been summoned, and re-checked this pull request!