feat(plugin): add namespaced hook API (#33416)

packages/core/test/plugin/fixtures/config-effect-plugin.ts

@@ -0,0 +1,15 @@
+import { define } from "@opencode-ai/plugin/v2/effect"
+import { Effect } from "effect"
+
+export default define({
+  id: "config-effect-plugin",
+  effect: (ctx) =>
+    ctx.agent
+      .transform((agents) => {
+        agents.update("effect-configured", (agent) => {
+          agent.description = ctx.options.description
+          agent.mode = "subagent"
+        })
+      })
+      .pipe(Effect.asVoid),
+})

packages/core/test/plugin/fixtures/config-promise-plugin.ts

@@ -0,0 +1,13 @@
+import { define } from "@opencode-ai/plugin/v2/promise"
+
+export default define({
+  id: "config-promise-plugin",
+  setup: async (ctx) => {
+    await ctx.agent.transform((agents) => {
+      agents.update("configured", (agent) => {
+        agent.description = ctx.options.description
+        agent.mode = "subagent"
+      })
+    })
+  },
+})

packages/core/test/plugin/fixtures/invalid-plugin.ts

@@ -0,0 +1 @@
+export default {}