feat: include default styles with the package import

[enumura1]

Summary

• make the normal package import include the default caption stylesheet in browser bundlers
• preserve CSS-free Node/SSR imports through conditional package exports
• let application CSS override the default classes and CSS variables by importing its stylesheet after GlyphFlow
• update the demo, README, and English/Japanese documentation
• prepare version 1.1.0 without publishing it

Validation

• npm run format:check
• npm run lint
• npm test (26 tests)
• npm run build (includes package-entry verification)
• npx vite build --config examples/basic/vite.config.ts
• npm run docs:build
• npm pack --dry-run --cache /tmp/glyphflow-npm-cache