Add multilang examples and CI check; expand README (CI/CD, preview)

[nesvet]

Description

Closes #6

What does this PR do?

Adds minimal sample projects in TypeScript, Python, Java, Go, and Rust under examples/, each with a generated fln snapshot (examples/*.md), and ensures those snapshots stay in sync in CI. Expands the README with a language-agnostic pitch, a CI/CD & Automation section (GitHub Actions snapshot workflow, pre-commit context guard), and a Preview section that links to the real example outputs instead of inline placeholders.

Changes

• Add examples/ with ts-app, python-app, java-app, go-app, rust-app (source + generated *.md snapshots)
• Add scripts/generate-examples.ts and bun run generate:examples to regenerate examples/*.md
• CI: new step “Examples up-to-date” (run generate:examples, then git diff --exit-code -- "examples/*.md")
• README: language-agnostic intro, bullet punctuation, “Auditable Snapshots” and “Dataset Preparation”, CI/CD subsection (Actions + pre-commit), Preview links to examples/*.md
• Add examples/README.md describing the layout and regeneration

Testing

• bun test passes
• bun run lint passes
• bun run typecheck passes

Checklist

• Updated documentation if needed (README, CONTRIBUTING, etc.)
• Added tests for new features or bug fixes
• Checked that the change doesn't break existing functionality