fix: decode asset URLs in dev when reading them

[Rich-Harris]

The read function from $app/server fails in development if the asset being read contains url-encoded characters in the filename. For example, if you have a file like content/[foo].txt, this will fail:

import { read } from '$app/server';

const files = import.meta.glob('./content/**', { eager: true, query: '?url' });
const data = await read(files['./content/[foo].txt'].default).text();

This PR fixes it by wrapping the asset URL in decodeURIComponent (but only in dev, as it's unnecessary in prod).

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Latest commit: b768312

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[hyunbinseo]

Does this fix the following issues?

• read() does not support filename with space on macOS #12265
• read() does not support pathnames with [param] on macOS #12266

I'm going to close this as a duplicate of #12265. They're both URL encoding issues.

[Rich-Harris]

Ah nice! Yes, those should be fixed now - closing