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/web/config.mjs

@@ -0,0 +1,14 @@
+const stage = process.env.SST_STAGE || "dev"
+
+export default {
+  url: stage === "production" ? "https://opencode.ai" : `https://${stage}.opencode.ai`,
+  console: stage === "production" ? "https://opencode.ai/auth" : `https://${stage}.opencode.ai/auth`,
+  email: "help@anoma.ly",
+  socialCard: "https://social-cards.sst.dev",
+  github: "https://github.com/anomalyco/opencode",
+  discord: "https://opencode.ai/discord",
+  headerLinks: [
+    { name: "app.header.home", url: "/" },
+    { name: "app.header.docs", url: "/docs/" },
+  ],
+}