v1.28.0 - Opus default + vision

API: Opus by default + image support

• Default model is now claude-opus-4-8 when a request names none (or a non-Claude id).
• Vision / images: /v1/chat/completions and /v1/messages accept images - OpenAI image_url parts (data: or https URLs) and native Anthropic image blocks - forwarded to Claude Code's vision.
• Dashboard Playground: "Enable agent tools" is now a switch (default on), added an image picker, and the model list defaults to Opus.

Docs: https://fjrg2007.github.io/enigma/docs/concepts/api/