Describe the bug

When a chunk imports another chunk with css included, then it is not using the chunk-id, but the content hash instead.

The content of the referencing js file is changing, but the content-hash stays the same.

Reproduction

This commit is showcasing the diff when style.module.css changes:
plusgut/vite-importmap-csschunk@a7fb132

Steps to reproduce

style.module.css

.foo {
  color: blue;
}

-> lazy-Cvj1z_cO.css

._foo_y7qhu_1 {
  color: blue;
}

lazy.js

import style from './style.module.css'

document.querySelector('#app').innerHTML = `<div class="${style.foo}">test</div>`

-> lazy-kzD5pkGc.js

var style_module_default = { foo: "_foo_y7qhu_1" };
document.querySelector("#app").innerHTML = `<div class="${style_module_default.foo}">test</div>`;

main.js
import("lazy.js")
-> index-CxpEbBJD.js

__vite__mapDeps,d=(m.f||(m.f=["assets/lazy-BxW4EhTm.js","assets/lazy-Cvj1z_cO.css"]))

Note that above the lazy.js import got the chunk-id instead of the content-hash, but the css import got the content-hash.

When now the css gets changed color: blue to red it gets a new content-hash "lazy-BzzqbZnv.css"

And lazy.js also gets a new content-hash since the css-module-selectors are not stable
lazy.js ->lazy-Coo9y-m2.js

var style_module_default = { foo: "_foo_n3gm1_1" };

document.querySelector("#app").innerHTML = `<div class="${style_module_default.foo}">test</div>`;

And now the flaw is that the content-hash of main.js stays the same but the content changed
index-CxpEbBJD.js

__vite__mapDeps,d=(m.f||(m.f=["assets/lazy-BxW4EhTm.js","assets/lazy-BzzqbZnv.css"]

When now a browser with cached files from the previous builds hits the site, it reads the old index-CxpEbBJD.js
and fetches the new lazy-Coo9y-m2.js from the importmap and stays on the old lazy-Cvj1z_cO.css
And no css gets applied, because the new css-class _foo_n3gm1_1 does not exist in the old css file.

System Info

System:
    OS: Linux 7.0 cpe:/o:nixos:nixos:26.05 26.05 (Yarara)
    CPU: (8) x64 Intel(R) Core(TM) i7-8565U CPU @ 1.80GHz
    Memory: 12.07 GB / 15.29 GB
    Container: Yes
    Shell: 4.6.0 - /run/current-system/sw/bin/fish
  Binaries:
    Node: 24.14.0 - /nix/store/v2210ar51jddnrcx46m53ivv9palc26m-nodejs-24.14.0/bin/node
    npm: 11.9.0 - /nix/store/v2210ar51jddnrcx46m53ivv9palc26m-nodejs-24.14.0/bin/npm
  Browsers:
    Chromium: 147.0.7727.55
    Firefox: 149.0.2
    Firefox Developer Edition: 149.0.2
  npmPackages:
    vite: ^8.1.1 => 8.1.4

Used Package Manager

npm

Logs

No response

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