feat(presets): add Amux provider preset for 6 apps

Non-partner aggregator across Claude Code, Claude Desktop, Codex,
OpenCode, OpenClaw, and Hermes. Claude Code uses bare host
api.amux.ai; Codex uses /v1 native Responses; the other three apps
default to gpt-5.5. No Gemini preset. Registers the amux inline icon
(currentColor) in the icon index and metadata.

src/config/opencodeProviderPresets.ts

@@ -424,6 +424,32 @@ export const opencodeProviderPresets: OpenCodeProviderPreset[] = [
       },
     },
   },
+  {
+    name: "Amux",
+    websiteUrl: "https://amux.ai",
+    apiKeyUrl: "https://amux.ai",
+    settingsConfig: {
+      npm: "@ai-sdk/openai-compatible",
+      name: "Amux",
+      options: {
+        baseURL: "https://api.amux.ai/v1",
+        apiKey: "",
+        setCacheKey: true,
+      },
+      models: {
+        "gpt-5.5": { name: "GPT-5.5" },
+      },
+    },
+    category: "aggregator",
+    icon: "amux",
+    templateValues: {
+      apiKey: {
+        label: "API Key",
+        placeholder: "",
+        editorValue: "",
+      },
+    },
+  },
   {
     name: "火山Agentplan",
     websiteUrl: "https://www.volcengine.com/product/ark",