fix broken svelte example

[kenricqq]

Summary

Fixes the Svelte example so it renders correctly.

Problem

Running zig build run showed a blank page despite a non-empty App.svelte.

Changes

• Updates the Svelte example to match Svelte 5 behavior

Before

After

Testing

• Ran zig build run successfully
• Confirmed the Svelte example renders correctly

[vercel]

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[ctate]

Hey @kenricqq - thanks for your contribution! Can you please sign your commit(s)?

[kenricqq]

@ctate Commit signed!

[Sc3l3t0n]

Hi, not sure if this is the right place to mention it, but I noticed the same pattern also exists in the project initializer template.

Since this PR updates the Svelte example for Svelte 5 by switching from new App(...) to mount(App, ...), should src/tooling/templates.zig be updated as well so newly generated Svelte projects use the same entrypoint?

Specifically, svelteMainJs() should probably change from:

src/tooling/templates.zig:1560

fn svelteMainJs() []const u8 {
    return
    \\import App from "./App.svelte";
    \\import "./app.css";
    \\
    \\const app = new App({ target: document.getElementById("app") });
    \\
    \\export default app;
    \\
    ;
}

to

fn svelteMainJs() []const u8 {
    return
    \\import { mount } from "svelte";
    \\import App from "./App.svelte";
    \\import "./app.css";
    \\
    \\const app = mount(App, { target: document.getElementById("app") });
    \\
    \\export default app;
    \\
    ;
}

Otherwise the checked-in example is fixed, but projects created through the initializer may still get the old Svelte 4-style bootstrap code.