Various build shenenigans (#5)

This PR extends the build pipeline of the www service to support
locale-prefixed static builds (EN/RU) with build-time SSG output
injection, while also refactoring UI typography to a tokenized Tailwind
v4 @theme-driven approach.

Changes:

- Add build-time SSG plugin to @ermnvldmr/rsbuild-config and wire
multi-locale builds (/en/, /ru/) into services/www.
- Introduce new @ermnvldmr/i18n package (locale constants, path helpers,
keysets, pluralization) and apply it to www navigation/text.
- Refactor ui typography to a shared getTypographyClassNames utility +
Tailwind token definitions, with stl/cn updated for correct
Tailwind-merge behavior.

services/www/rsbuild.config.ts

@@ -1,32 +1,71 @@
-import { defineServiceConfig, discoverEntries } from '@ermnvldmr/rsbuild-config/dev';
+import { defineServiceConfig, discoverEntries, mergeConfig } from '@ermnvldmr/rsbuild-config/dev';
 import { THEME_INIT_SCRIPT, THEME_INIT_STYLES } from '@ermnvldmr/ui/dev';
+import { localeRsbuildConfig } from '@ermnvldmr/i18n/dev';
+import { RsdoctorRspackPlugin } from '@rsdoctor/rspack-plugin';
 import { pluginMdx } from '@rsbuild/plugin-mdx';
 import remarkFrontmatter from 'remark-frontmatter';
 import remarkMdxFrontmatter from 'remark-mdx-frontmatter';
 
-export default defineServiceConfig({
-  plugins: [
-    pluginMdx({
-      mdxLoaderOptions: {
-        remarkPlugins: [remarkFrontmatter, [remarkMdxFrontmatter, { name: 'frontmatter' }]],
-      },
-    }),
-  ],
-  source: {
-    entry: discoverEntries(import.meta.dirname, './src/app/**/*.tsx'),
-  },
-  html: {
-    tags: [
-      {
-        tag: 'script',
-        children: THEME_INIT_SCRIPT,
-        head: true,
-      },
-      {
-        tag: 'style',
-        children: THEME_INIT_STYLES,
-        head: true,
+const fontBase = 'static/font';
+
+export default defineServiceConfig(
+  mergeConfig(localeRsbuildConfig(), {
+    tools: {
+      rspack: {
+        plugins: [
+          process.env.RSDOCTOR === 'true' &&
+            new RsdoctorRspackPlugin({
+              disableClientServer: true,
+              output: { reportDir: './rsdoctor', mode: 'brief' },
+            }),
+        ].filter(Boolean),
       },
+    },
+    plugins: [
+      pluginMdx({
+        mdxLoaderOptions: {
+          remarkPlugins: [remarkFrontmatter, [remarkMdxFrontmatter, { name: 'frontmatter' }]],
+        },
+      }),
     ],
-  },
-});
+    source: {
+      entry: discoverEntries(import.meta.dirname, './src/app/**/*.tsx'),
+    },
+    html: {
+      tags: [
+        { tag: 'script', children: THEME_INIT_SCRIPT, head: true },
+        { tag: 'style', children: THEME_INIT_STYLES, head: true },
+        {
+          tag: 'link',
+          attrs: {
+            rel: 'preload',
+            as: 'font',
+            type: 'font/woff2',
+            href: `${fontBase}/lato-400.woff2`,
+            crossorigin: true,
+          },
+        },
+        {
+          tag: 'link',
+          attrs: {
+            rel: 'preload',
+            as: 'font',
+            type: 'font/woff2',
+            href: `${fontBase}/lato-700.woff2`,
+            crossorigin: true,
+          },
+        },
+        {
+          tag: 'link',
+          attrs: {
+            rel: 'preload',
+            as: 'font',
+            type: 'font/woff2',
+            href: `${fontBase}/eb-garamond-var.woff2`,
+            crossorigin: true,
+          },
+        },
+      ],
+    },
+  })
+);