test: unit coverage for conductor-env-shim

Refactor lib/conductor-env-shim.ts to export promoteConductorEnv()
so unit tests can manipulate env and call it directly (a bare side-
effect IIFE on import isn't reachable from bun:test once cached).
The on-import IIFE still runs — existing four-entry-point imports
keep working unchanged.

test/conductor-env-shim.test.ts covers all three branches:
GSTACK_FOO present + FOO empty → promotion; FOO already set →
no-overwrite; nothing in env → no-op.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

lib/conductor-env-shim.ts

@@ -7,8 +7,12 @@
  *
  * Import this for its side effect: `import "../lib/conductor-env-shim";`
  */
-for (const key of ["ANTHROPIC_API_KEY", "OPENAI_API_KEY"] as const) {
-  if (!process.env[key] && process.env[`GSTACK_${key}`]) {
-    process.env[key] = process.env[`GSTACK_${key}`];
+export function promoteConductorEnv(): void {
+  for (const key of ["ANTHROPIC_API_KEY", "OPENAI_API_KEY"] as const) {
+    if (!process.env[key] && process.env[`GSTACK_${key}`]) {
+      process.env[key] = process.env[`GSTACK_${key}`];
+    }
   }
 }
+
+promoteConductorEnv();

test/conductor-env-shim.test.ts

@@ -0,0 +1,46 @@
+import { describe, test, expect, beforeEach, afterEach } from 'bun:test';
+import { promoteConductorEnv } from '../lib/conductor-env-shim';
+
+describe('conductor-env-shim', () => {
+  const KEYS = ['ANTHROPIC_API_KEY', 'OPENAI_API_KEY', 'GSTACK_ANTHROPIC_API_KEY', 'GSTACK_OPENAI_API_KEY'] as const;
+  const saved: Record<string, string | undefined> = {};
+
+  beforeEach(() => {
+    for (const k of KEYS) {
+      saved[k] = process.env[k];
+      delete process.env[k];
+    }
+  });
+
+  afterEach(() => {
+    for (const k of KEYS) {
+      if (saved[k] === undefined) delete process.env[k];
+      else process.env[k] = saved[k];
+    }
+  });
+
+  test('promotes GSTACK_ANTHROPIC_API_KEY to ANTHROPIC_API_KEY when canonical is empty', () => {
+    process.env.GSTACK_ANTHROPIC_API_KEY = 'sk-ant-test-123';
+    promoteConductorEnv();
+    expect(process.env.ANTHROPIC_API_KEY).toBe('sk-ant-test-123');
+  });
+
+  test('promotes GSTACK_OPENAI_API_KEY to OPENAI_API_KEY when canonical is empty', () => {
+    process.env.GSTACK_OPENAI_API_KEY = 'sk-oai-test-456';
+    promoteConductorEnv();
+    expect(process.env.OPENAI_API_KEY).toBe('sk-oai-test-456');
+  });
+
+  test('does not overwrite canonical when both canonical and GSTACK_-prefixed are set', () => {
+    process.env.ANTHROPIC_API_KEY = 'sk-ant-original';
+    process.env.GSTACK_ANTHROPIC_API_KEY = 'sk-ant-prefixed';
+    promoteConductorEnv();
+    expect(process.env.ANTHROPIC_API_KEY).toBe('sk-ant-original');
+  });
+
+  test('no-op when neither canonical nor GSTACK_-prefixed are set', () => {
+    promoteConductorEnv();
+    expect(process.env.ANTHROPIC_API_KEY).toBeUndefined();
+    expect(process.env.OPENAI_API_KEY).toBeUndefined();
+  });
+});