Missing field for form doesn't report error

Describe the bug

Currently when you create a remote form, you must use the {...form.fields.field.as(...)} syntax when making a form field, but if you forget to add this for one of the required fields, nothing will happen at all. No errors will get thrown, no warnings indicating something is wrong, just nothing will happen on the form submit.

(Also I find it weird that the syntax now required, whereas before it worked fine using the standard name="name" value="value" type="text", but that's not the point of this)

Reproduction

Here is what I managed to make on stack blitz

https://stackblitz.com/edit/sveltejs-kit-template-default-cb8vsuzs?file=src%2Froutes%2F%2Bpage.svelte

Just add the other form field and remove it, and see that nothing happens.

Logs

System Info

OS: macOS 26.0.1
CPU: arm64 Apple M3 Pro
Memory: 97.94 MB / 18.00 GB
Shell: 5.9 - /bin/zsh

Node: 20.19.4
npm: 10.8.2
bun: 1.3.2

Browser: Zen 1.16.4b (Firefox 143.0.4)

Severity

serious, but I can work around it

Additional Information

This is just quite annoying, spent a load of time debugging loads of my forms because of this, also dynamic forms (Record<string, boolean> for example) are also having issues because of this, still trying to see if I can fix that though.

Start with the linked StackBlitz reproduction and trace the remote form submission behavior around the {...form.fields.field.as(...)} syntax. Check what happens when a required field is omitted, then verify that the form reports an error or warning instead of failing silently; consider the noted dynamic-form case if it is covered by the same path.