fix: address cubic 4/5 review issues

- Preserve encoding/callback args in stdout.write wrapper (json-output.ts)
- Restore global console spy in afterEach (server-connection.test.ts)
- Restore console.error spy in afterEach (on-complete-hook.test.ts)

src/cli/run/server-connection.test.ts

@@ -1,5 +1,7 @@
 import { describe, it, expect, mock, beforeEach, afterEach } from "bun:test"
 
+const originalConsole = globalThis.console
+
 const mockServerClose = mock(() => {})
 const mockCreateOpencode = mock(() =>
   Promise.resolve({
@@ -36,6 +38,10 @@ describe("createServerConnection", () => {
     globalThis.console = { ...console, log: mockConsoleLog } as typeof console
   })
 
+  afterEach(() => {
+    globalThis.console = originalConsole
+  })
+
   it("attach mode returns client with no-op cleanup", async () => {
     // given
     const signal = new AbortController().signal