feat: 品牌替换 + 启动优化 + AGENTS.md 模板定制

- 品牌替换：OpenCode/opencode → AirCoding/aircoding（16+ 文件）
- Logo ASCII art：修复 left/right 行数不匹配导致的启动崩溃
- 启动诊断：添加 OPENCODE_PRINT_TIMING 计时探针
- dev 模式默认 --pure 跳过外部插件加载
- AGENTS.md 模板：追加 AirCoding 多 Agent 专项段落
- architect prompt + plugin：强化 AGENTS.md 产出验证

packages/core/test/model-request.test.ts

@@ -0,0 +1,44 @@
+import { describe, expect, test } from "bun:test"
+import { ModelRequest } from "@opencode-ai/core/model-request"
+
+describe("ModelRequest", () => {
+  test("partitions AI SDK model and models.dev mode options", () => {
+    expect(
+      ModelRequest.normalizeAiSdkOptions("@ai-sdk/openai", {
+        maxOutputTokens: 4096,
+        temperature: 0.2,
+        reasoningEffort: "high",
+        serviceTier: "priority",
+        custom_extension: { enabled: true },
+      }),
+    ).toEqual({
+      generation: { maxTokens: 4096, temperature: 0.2 },
+      options: { reasoningEffort: "high", serviceTier: "priority" },
+      body: { custom_extension: { enabled: true } },
+    })
+  })
+
+  test("keeps unknown-provider options as compatibility fields", () => {
+    expect(ModelRequest.normalizeAiSdkOptions(undefined, { temperature: 0.2, reasoningEffort: "high" })).toEqual({
+      generation: { temperature: 0.2 },
+      options: {},
+      body: { reasoningEffort: "high" },
+    })
+  })
+
+  test("does not consult inherited package-name properties", () => {
+    expect(ModelRequest.normalizeAiSdkOptions("__proto__", { reasoningEffort: "high" })).toEqual({
+      generation: {},
+      options: {},
+      body: { reasoningEffort: "high" },
+    })
+  })
+
+  test("normalizes models.dev wire aliases owned by native protocols", () => {
+    expect(ModelRequest.normalizeAiSdkOptions("@ai-sdk/openai", { service_tier: "priority" })).toEqual({
+      generation: {},
+      options: { serviceTier: "priority" },
+      body: {},
+    })
+  })
+})