AbstractVision v0.2.4

• Playground: add a self-contained abstractvision playground command that serves both the web UI and /v1/vision/* API locally, so playground testing no longer depends on an AbstractCore server.
• Playground: package the HTML asset in the wheel, default the UI to the serving origin, and avoid stale persisted API URLs that could keep calling an older AbstractCore endpoint.
• Playground model loading: accept raw Hugging Face ids such as runwayml/stable-diffusion-v1-5 directly, while still accepting explicit backend prefixes like diffusers/..., sdcpp/..., and openai-compatible/....
• Packaging/CI: keep AbstractCore out of AbstractVision dependency metadata and test workflows; AbstractCore remains an optional host integration loaded lazily when present.
• Docs/tests: refresh playground docs around the self-contained local server and add coverage for cached model listing, raw model loading, playground jobs, and tool integration without installing AbstractCore.