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/lib/websocket.ts

@@ -0,0 +1,46 @@
+export class FakeWebSocket {
+  static CONNECTING = 0
+  static OPEN = 1
+  static CLOSING = 2
+  static CLOSED = 3
+
+  readyState = FakeWebSocket.CONNECTING
+  closed = false
+  sent: string[] = []
+  listeners = new Map<string, Set<(event: { data?: unknown }) => void>>()
+
+  constructor(
+    readonly url: string,
+    readonly options?: { headers?: Record<string, string> },
+  ) {}
+
+  addEventListener(type: string, listener: (event: { data?: unknown }) => void) {
+    const current = this.listeners.get(type) ?? new Set<(event: { data?: unknown }) => void>()
+    current.add(listener)
+    this.listeners.set(type, current)
+  }
+
+  send(data: string) {
+    this.sent.push(data)
+  }
+
+  close() {
+    if (this.readyState === FakeWebSocket.CLOSED) return
+    this.closed = true
+    this.readyState = FakeWebSocket.CLOSED
+    this.emit("close", {})
+  }
+
+  open() {
+    this.readyState = FakeWebSocket.OPEN
+    this.emit("open", {})
+  }
+
+  message(data: unknown) {
+    this.emit("message", { data })
+  }
+
+  emit(type: string, event: { data?: unknown }) {
+    this.listeners.get(type)?.forEach((listener) => listener(event))
+  }
+}