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.

packages/rsbuild-config/package.json

@@ -12,8 +12,10 @@
   "dependencies": {
     "@rsbuild/plugin-react": "^1.1.1",
     "@rsbuild/plugin-type-check": "^1.1.1",
+    "critters": "^0.0.25",
     "fast-glob": "^3.3.3",
     "jsdom": "^28.0.0",
+    "react": "^19.1.0",
     "rsbuild-plugin-dts": "^0.19.5"
   },
   "devDependencies": {