Uninitialized EventTarget vtable causes alignment panic

[axlEscalada]

Browser crashes with alignment panic when js creates EventTarget instances:

thread 2227839 panic: incorrect alignment
/home/axl/projects/browser/src/browser/netsurf.zig:623:93: 0x358c8f0 in eventTargetVtable (lightpanda)
    const vtable_aligned: *align(@alignOf([*c]c.dom_event_target_vtable)) const anyopaque = @alignCast(vtable);
                                                                                            ^
/home/axl/projects/browser/src/browser/netsurf.zig:791:34: 0x358c79d in eventTargetDispatchEvent (lightpanda)
    const err = eventTargetVtable(et).dispatch_event.?(et, event, &res);
                                 ^
/home/axl/projects/browser/src/browser/dom/event_target.zig:160:56: 0x38d608d in _dispatchEvent (lightpanda)
        const res = try parser.eventTargetDispatchEvent(self, event);
                                                       ^
/home/axl/projects/browser/src/browser/js/Caller.zig:100:5: 0x38d66de in method__anon_306243 (lightpanda)
    const res = @call(.auto, func, args);
    ^
/home/axl/projects/browser/src/browser/js/Env.zig:339:26: 0x3711a82 in callback (lightpanda)
            caller.method(Struct, named_function, info) catch |err| {
                         ^
???:?:?: 0x707c0c6 in ??? (???)

Steps to reproduce:

./lightpanda serve --host 127.0.0.1 --port 9222

Then run:

import { chromium } from 'playwright';
 
const browser = await chromium.connectOverCDP('ws://127.0.0.1:9222');
 
const context = await browser.newContext({});
const page = await context.newPage();
 
await page.goto('https://github.com/');
 
const title = await page.locator('h1').textContent();
console.log(title);
 
await page.close();
await context.close();
await browser.close();

Environment:

• OS: Linux (tested on NixOS)
• Zig version: 0.15.2
• Architecture: x86_64