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/app/public/oc-theme-preload.js

@@ -0,0 +1,39 @@
+;(function () {
+  var key = "opencode-theme-id"
+  var themeId = localStorage.getItem(key) || "oc-2"
+
+  if (themeId === "oc-1") {
+    themeId = "oc-2"
+    localStorage.setItem(key, themeId)
+    localStorage.removeItem("opencode-theme-css-light")
+    localStorage.removeItem("opencode-theme-css-dark")
+  }
+
+  var scheme = localStorage.getItem("opencode-color-scheme") || "system"
+  var isDark = scheme === "dark" || (scheme === "system" && matchMedia("(prefers-color-scheme: dark)").matches)
+  var mode = isDark ? "dark" : "light"
+
+  document.documentElement.dataset.theme = themeId
+  document.documentElement.dataset.colorScheme = mode
+
+  // Update theme-color meta tag to match app color scheme
+  var metas = document.querySelectorAll("meta[name='theme-color']")
+  if (metas.length > 0) metas[0].setAttribute("content", isDark ? "#131010" : "#F8F7F7")
+
+  if (themeId === "oc-2") return
+
+  var css = localStorage.getItem("opencode-theme-css-" + mode)
+  if (css) {
+    var style = document.createElement("style")
+    style.id = "oc-theme-preload"
+    style.textContent =
+      ":root{color-scheme:" +
+      mode +
+      ";--text-mix-blend-mode:" +
+      (isDark ? "plus-lighter" : "multiply") +
+      ";" +
+      css +
+      "}"
+    document.head.appendChild(style)
+  }
+})()