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.

ci/docker/www/Dockerfile

@@ -16,6 +16,7 @@ COPY packages/rsbuild-config/package.json ./packages/rsbuild-config/
 COPY packages/stl/package.json ./packages/stl/
 COPY packages/storybook-config/package.json ./packages/storybook-config/
 COPY packages/ui/package.json ./packages/ui/
+COPY packages/i18n/package.json ./packages/i18n/
 COPY services/www/package.json ./services/www/
 
 # Install dependencies
@@ -27,10 +28,11 @@ COPY . .
 # Build dependencies
 RUN pnpm --filter @ermnvldmr/rsbuild-config build
 RUN pnpm --filter @ermnvldmr/stl build
+RUN pnpm --filter @ermnvldmr/i18n build
 RUN pnpm --filter @ermnvldmr/ui build
 
-# Build the website
-RUN pnpm --filter @ermnvldmr/www build
+# Build the website (all locales)
+RUN pnpm --filter @ermnvldmr/www build:all
 
 # Stage 2: Runtime
 FROM nginx:alpine