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/src/cli/cmd/debug/skill.ts

@@ -0,0 +1,15 @@
+import { EOL } from "os"
+import { Effect } from "effect"
+import { Skill } from "../../../skill"
+import { effectCmd } from "../../effect-cmd"
+
+export const SkillCommand = effectCmd({
+  command: "skill",
+  describe: "list all available skills",
+  builder: (yargs) => yargs,
+  handler: Effect.fn("Cli.debug.skill")(function* () {
+    const skill = yield* Skill.Service
+    const skills = yield* skill.all()
+    process.stdout.write(JSON.stringify(skills, null, 2) + EOL)
+  }),
+})