feat(plugin): add v2 effect host (#33111)

packages/plugin/src/v2/effect/command.ts

@@ -0,0 +1,15 @@
+import type { CommandV2Info } from "@opencode-ai/sdk/v2/types"
+import type { Effect } from "effect"
+import type { Transformable } from "./registration.js"
+
+export interface CommandDraft {
+  list(): readonly CommandV2Info[]
+  get(name: string): CommandV2Info | undefined
+  update(name: string, update: (command: CommandV2Info) => void): void
+  remove(name: string): void
+}
+
+export interface Command extends Transformable<CommandDraft> {
+  get(name: string): Effect.Effect<CommandV2Info | undefined>
+  list(): Effect.Effect<CommandV2Info[]>
+}