Regex based redirects for Static Web Apps

When migrating a blog to Azure Static Web Apps, the built-in route configuration lacks support for regex-based redirects with back-references. A workaround uses an Azure Function as a navigation fallback: unresolved paths are routed to the function via `navigationFallback` in `staticwebapp.config.json`, the original URL is read from the `x-ms-original-url` header, and JavaScript's `String.replace()` with regex capturing groups handles the redirect logic. Redirect rules are stored in a JSON file and matched at runtime, returning 301 redirects on match or a custom 404 page otherwise. A sample TypeScript project with GitHub Actions deployment workflow is provided.