Feature request: official Dart server-side SDK

**Is your feature request related to a problem?**

We run a production backend on **server-side Dart** (Firebase Cloud Functions, Dart AOT runtime) alongside our Flutter app. Today the only way to call the **Cloudinary** API from Dart is a hand-rolled HTTP client over the REST API — no typed models, no maintained auth/retry/pagination helpers, and drift whenever the API changes.

**Describe the solution you'd like**

An official (or officially-supported) **Dart package** published on [pub.dev](https://pub.dev), equivalent in scope to your Node.js SDK. Dart is now a first-class server language (AOT Cloud Functions, Cloud Run, Dart Frog, Serverpod), and the Flutter ecosystem makes one language across mobile + backend valuable.

**Alternatives considered**

- Hand-written REST client over `package:http` (current approach — high maintenance).
- Keeping these integrations in a separate Node.js service purely because no Dart SDK exists.

**Additional context**

Our team maintains both a Flutter app and a Dart backend; a Dart SDK would let us consolidate. Happy to help test and give feedback.

No implementation files or tests are identified in the issue. Start by reviewing the existing Node.js SDK and the Cloudinary REST API surface, then define the Dart package scope, supported helpers, and maintenance expectations. Done would mean an officially supported Dart package is implemented, published on pub.dev, and validated against the agreed API scope.

Written by the indexing model from the issue text.