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/specs/effect/migration.md

@@ -0,0 +1,62 @@
+# Effect Migration Patterns
+
+This is the compact reference for moving code toward the current Effect
+shape. The high-level roadmap is [`todo.md`](./todo.md); examples and
+rules are in [`guide.md`](./guide.md).
+
+## Default Shape
+
+- Service methods return `Effect`.
+- Service methods are named with `Effect.fn("Domain.method")`.
+- Expected failures are typed errors on the error channel.
+- Dependencies are yielded once at layer construction and closed over by
+  methods.
+- `defaultLayer` wires production dependencies; tests can use open layers
+  when replacing dependencies.
+
+## Instance State
+
+Use `InstanceState` for per-directory state, subscriptions, scoped
+background work, and per-instance cleanup.
+
+Do not add ad hoc `started` flags on top of `InstanceState`; the scoped
+cache handles run-once and concurrent deduplication.
+
+## Runtime Boundaries
+
+Prefer `AppRuntime` for crossing from non-Effect code into the shared app
+layer.
+
+`makeRuntime(...)` exists for intentional service-local boundaries and
+legacy facades. Do not add new service-local runtimes unless the service is
+genuinely outside `AppLayer`.
+
+## Platform Edges
+
+- Use `FSUtil.Service` instead of raw filesystem APIs in
+  effectified services.
+- Use `AppProcess.Service` instead of raw process wrappers.
+- Use `HttpClient.HttpClient` instead of raw `fetch` in Effect code.
+- Use `Effect.cached` for shared in-flight work.
+- Use `Effect.callback` for callback APIs.
+
+## Tests During Migration
+
+When migrating code, migrate touched tests toward
+[`test/EFFECT_TEST_MIGRATION.md`](../../test/EFFECT_TEST_MIGRATION.md):
+
+- `testEffect(...)`
+- `it.effect`, `it.live`, or `it.instance`
+- explicit layers for behavior changes
+- deterministic waits instead of sleeps
+- no mutable env/global flags after layers are built
+
+## Migration Checklist
+
+- [ ] The code has a single Effect body instead of Promise wrappers around
+      service calls.
+- [ ] Expected failures are typed errors, not thrown exceptions or defects.
+- [ ] Layer requirements are explicit.
+- [ ] Tests use Effect-aware fixtures and focused layers.
+- [ ] Public behavior and wire shapes are preserved unless intentionally
+      changed.