fix(web): match css-loader path on Windows for .prefix.css modules

The webpack CSS-rule customization detected css-loader via
`use.loader.includes("/css-loader/")`, which only matches POSIX-style
paths. On Windows the loader path uses backslashes
(`...\node_modules\css-loader\...`), so the check never matched and the
`.prefix.css` -> CSS-modules rule (localIdentName `lsf-[local]`) was
never inserted. Every `.prefix.css` import then compiled to empty
exports ("module has no exports" warnings) and the Data Manager / editor
rendered completely unstyled on Windows.

Match both separators with `/[\\/]css-loader[\\/]/` so the rule applies
on Windows as well as POSIX. No behavior change on POSIX.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: angwm1

web/webpack.config.js

@@ -157,7 +157,7 @@ module.exports = composePlugins(
         );
 
         const innerTest = oneOfRule.test?.toString() ?? "";
-        const cssLoader = oneOfRule.use.find((use) => use.loader?.includes("/css-loader/"));
+        const cssLoader = oneOfRule.use.find((use) => /[\\/]css-loader[\\/]/.test(use.loader ?? ""));
 
         if (innerTest.includes("module") && cssLoader?.options) {
           cssLoader.options.modules = {
@@ -173,7 +173,7 @@ module.exports = composePlugins(
       rule.oneOf.forEach((oneOfRule, idx) => {
         if (!oneOfRule.test || !oneOfRule.use) return;
         const t = oneOfRule.test.toString();
-        if (/^\/\\\.css\$\/$/.test(t) && oneOfRule.use.some((u) => u.loader?.includes("/css-loader/"))) {
+        if (/^\/\\\.css\$\/$/.test(t) && oneOfRule.use.some((u) => /[\\/]css-loader[\\/]/.test(u.loader ?? ""))) {
           insertions.push(idx);
         }
       });
@@ -183,7 +183,7 @@ module.exports = composePlugins(
         const template = rule.oneOf[idx];
         const prefixUse = template.use.map((u) => {
           if (typeof u === "string") return u;
-          if (u.loader?.includes("/css-loader/")) {
+          if (/[\\/]css-loader[\\/]/.test(u.loader ?? "")) {
             return {
               ...u,
               options: {