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

.opencode/opencode.jsonc

@@ -0,0 +1,20 @@
+{
+  "$schema": "https://opencode.ai/config.json",
+  "provider": {},
+  "permission": {},
+  "references": {
+    "effect": {
+      "repository": "github.com/Effect-TS/effect-smol",
+      "description": "Use for Effect v4 and effect-smol implementation details",
+    },
+    "opencode-local": {
+      "path": "~/.local/share/opencode",
+      "description": "Contains opencode logs and data",
+    },
+  },
+  "mcp": {},
+  "tools": {
+    "github-triage": false,
+    "github-pr-search": false,
+  },
+}