fix(www): resolve SSG build issues with font preloads, dark theme and… (#7)

… RU locale

- Fix depth-dependent duplicate font preload prefixes by using
locale-absolute fontBase path and publicPath:false on html.tags to
prevent Rsbuild from re-applying assetPrefix (path.posix.join behavior
with MPA nested entries)
- Fix .dark CSS rule stripped by critters: set reduceInlineStyles:false
so critters only processes external stylesheets and leaves inline theme
init styles (THEME_INIT_STYLES) intact
- Fix NormalModuleReplacementPlugin lost in mergeConfig: refactored
locale MDX replacement from tools.rspack function into a proper Rsbuild
plugin so mergeConfig concatenates plugin arrays correctly (enables RU
locale articles)
- Extend Critters type declaration to include reduceInlineStyles option

Made-with: Cursor

packages/rsbuild-config/src/lib/config/ssg.ts

@@ -111,6 +111,7 @@ export function ssgPlugin(): RsbuildPlugin {
           preload?: string;
           inlineFonts?: boolean;
           pruneSource?: boolean;
+          reduceInlineStyles?: boolean;
         }) => { process(html: string): Promise<string> };
 
         // critters `path` is the filesystem root that corresponds to publicPath.
@@ -121,9 +122,10 @@ export function ssgPlugin(): RsbuildPlugin {
         const critters = new Critters({
           path: webDistPath,
           publicPath: configuredAssetPrefix,
-          preload: 'swap',     // <link rel="preload" as="style" onload="this.rel='stylesheet'">
-          inlineFonts: false,  // fonts are handled via separate <link rel="preload"> tags
-          pruneSource: false,  // keep full CSS file for post-hydration correctness
+          preload: 'swap',              // <link rel="preload" as="style" onload="this.rel='stylesheet'">
+          inlineFonts: false,           // fonts are handled via separate <link rel="preload"> tags
+          pruneSource: false,           // keep full CSS file for post-hydration correctness
+          reduceInlineStyles: false,    // preserve theme init styles (prevents .dark rule from being stripped)
         });
 
         for (const entryName of entryNames) {