feat: add X-Code partner provider preset for Claude, Codex and OpenCode

- Add X-Code provider presets with x-code.cn endpoint
- Fix ANTHROPIC_API_KEY to ANTHROPIC_AUTH_TOKEN in Claude preset
- Register x-code icon SVG in icon index
- Add partnerPromotion.x-code i18n keys for zh, en, ja locales

src/config/codexProviderPresets.ts

@@ -314,6 +314,23 @@ requires_openai_auth = true`,
     icon: "micu",
     iconColor: "#000000",
   },
+  {
+    name: "X-Code",
+    websiteUrl: "https://www.x-code.cn",
+    apiKeyUrl: "https://www.x-code.cn",
+    auth: generateThirdPartyAuth(""),
+    config: generateThirdPartyConfig(
+      "x-code",
+      "https://www.x-code.cn/v1",
+      "gpt-5.4",
+    ),
+    endpointCandidates: ["https://www.x-code.cn/v1"],
+    category: "third_party",
+    isPartner: true, // 合作伙伴
+    partnerPromotionKey: "x-code", // 促销信息 i18n key
+    icon: "x-code",
+    iconColor: "#000000",
+  },
   {
     name: "OpenRouter",
     websiteUrl: "https://openrouter.ai",