Remove Zod from named errors (#26982)

packages/opencode/test/util/error.test.ts

@@ -1,5 +1,9 @@
 import { describe, expect, test } from "bun:test"
+import { Schema } from "effect"
+import { NamedError } from "@opencode-ai/core/util/error"
 import { errorData, errorFormat, errorMessage } from "../../src/util/error"
+import { namedSchemaError } from "../../src/util/named-schema-error"
+import { UI } from "../../src/cli/ui"
 
 describe("util.error", () => {
   test("formats native Error instances", () => {
@@ -48,4 +52,18 @@ describe("util.error", () => {
     expect(data.message).toBe("ResolveMessage: Cannot resolve module")
     expect(String(data.formatted)).toContain("ResolveMessage")
   })
+
+  test("named schema errors are real NamedError instances", () => {
+    const ExampleError = namedSchemaError("ExampleError", { message: Schema.String })
+    const error = new ExampleError({ message: "boom" })
+
+    expect(error).toBeInstanceOf(NamedError)
+    expect(error.toObject()).toEqual({ name: "ExampleError", data: { message: "boom" } })
+  })
+
+  test("void named errors accept JSON without data", () => {
+    const serialized = JSON.parse(JSON.stringify(new UI.CancelledError(undefined).toObject()))
+
+    expect(Schema.decodeUnknownOption(UI.CancelledError.Schema)(serialized)._tag).toBe("Some")
+  })
 })