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/config/fixtures/weird-model-id.md

@@ -0,0 +1,13 @@
+---
+description: General coding and planning agent
+mode: subagent
+model: synthetic/hf:zai-org/GLM-4.7
+tools:
+  write: true
+  read: true
+  edit: true
+stuff: >
+  This is some stuff
+---
+
+Strictly follow da rules