feat(providers): add System One (Jev) decision endpoint

New /v1/systemone pass-through route for Jev decision models (jev-1.13,
jev-1.13-free) on OpenCode Zen and the free lane. Follows the media-route
pattern: systemoneConfig in the registry drives URL/headers, the handler
mirrors the embeddings account-fallback + usage flow, and the dashboard
gains a System One media-provider kind. No chat-pipeline changes.

Co-Authored-By: Claude Code <noreply@anthropic.com>

open-sse/providers/index.js

@@ -23,7 +23,7 @@ function buildTransport(transport, oauth) {
 const MEDIA_KEYS = new Set([
   "serviceKinds", "ttsConfig", "sttConfig", "embeddingConfig",
   "imageConfig", "imageToTextConfig", "videoConfig", "musicConfig",
-  "searchViaChat", "searchConfig", "fetchConfig",
+  "searchViaChat", "searchConfig", "fetchConfig", "systemoneConfig",
   "modelsFetcher", "mediaPriority", "hiddenKinds",
 ]);
 

open-sse/providers/registry/opencode-zen.js

@@ -106,7 +106,6 @@ export default {
     { id: "union-alpha", name: "Union Alpha", supportedFormats: ["claude"] },
     // Free tier on the keyed lane (chat completions)
     { id: "deepseek-v4-flash-free", name: "DeepSeek V4 Flash Free", supportedFormats: ["openai"] },
-    { id: "mimo-v2.6-flash-free", name: "MiMo V2.6 Flash Free", supportedFormats: ["openai"] },
     { id: "mimo-v2.5-free", name: "MiMo V2.5 Free", supportedFormats: ["openai"] },
     { id: "ling-3.0-flash-fin-free", name: "Ling 3.0 Flash Fin Free", supportedFormats: ["openai"] },
     { id: "nemotron-3-ultra-free", name: "Nemotron 3 Ultra Free", supportedFormats: ["openai"] },

open-sse/providers/registry/opencode.js

@@ -28,7 +28,16 @@ export default {
     { id: "muse-spark-1.2-contributor-free", name: "Muse Spark 1.2 Contributor Free", targetFormat: "openai-responses" },
     { id: "muse-spark-1.3-contributor-free", name: "Muse Spark 1.3 Contributor Free", targetFormat: "openai-responses" },
     { id: "union-alpha", name: "Union Alpha Free", targetFormat: "claude" },
+    { id: "jev-1.13-free", name: "Jev 1.13 Free", kind: "decision" },
   ],
+  serviceKinds: ["llm", "systemone"],
+  systemoneConfig: {
+    baseUrl: "https://opencode.ai/zen/v1/systemone",
+    headers: {
+      "x-opencode-client": "desktop",
+      "User-Agent": "opencode/1.18.31",
+    },
+  },
   modelsFetcher: { url: "https://opencode.ai/zen/v1/models", type: "opencode-free" },
   passthroughModels: true,
 };