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/opencode/test/fixture/config.ts

@@ -0,0 +1,23 @@
+import { Config } from "@/config/config"
+import { emptyConsoleState } from "@opencode-ai/core/v1/config/console-state"
+import { Effect, Layer } from "effect"
+
+export function make(overrides: Partial<Config.Interface> = {}) {
+  return Config.Service.of({
+    get: () => Effect.succeed({}),
+    getGlobal: () => Effect.succeed({}),
+    getConsoleState: () => Effect.succeed(emptyConsoleState),
+    update: () => Effect.void,
+    updateGlobal: (config) => Effect.succeed({ info: config, changed: false }),
+    invalidate: () => Effect.void,
+    directories: () => Effect.succeed([]),
+    waitForDependencies: () => Effect.void,
+    ...overrides,
+  })
+}
+
+export function layer(overrides?: Partial<Config.Interface>) {
+  return Layer.succeed(Config.Service, make(overrides))
+}
+
+export * as TestConfig from "./config"