Replace OpenAI SDK with Gradient SDK for AI features #29
Description
Currently SeaNotes uses the OpenAI SDK for AI-powered functionality. We want to fully migrate to using DigitalOcean’s Gradient AI SDK instead.
Acceptance Criteria:
- All places where the OpenAI SDK is imported and used are replaced with equivalent Gradient SDK calls.
- Tests (if any) modified to account for the new SDK.
- Documentation updated: Readme, env var config, examples.