refactor: add role agent plan ssot

src/role-agent-plan.test.ts

@@ -0,0 +1,63 @@
+import { describe, expect, it } from 'vitest';
+
+import { resolveRoleAgentPlan } from './role-agent-plan.js';
+
+describe('resolveRoleAgentPlan', () => {
+  it('uses the group agent type as owner in single rooms', () => {
+    expect(
+      resolveRoleAgentPlan({
+        paired: false,
+        groupAgentType: 'codex',
+        configuredReviewer: 'claude-code',
+        configuredArbiter: 'claude-code',
+      }),
+    ).toEqual({
+      ownerAgentType: 'codex',
+      reviewerAgentType: null,
+      arbiterAgentType: null,
+    });
+  });
+
+  it('falls back to claude-code when group agent type is undefined', () => {
+    expect(
+      resolveRoleAgentPlan({
+        paired: false,
+        groupAgentType: undefined,
+        configuredReviewer: 'codex',
+      }),
+    ).toEqual({
+      ownerAgentType: 'claude-code',
+      reviewerAgentType: null,
+      arbiterAgentType: null,
+    });
+  });
+
+  it('uses configured reviewer and arbiter when paired room roles differ', () => {
+    expect(
+      resolveRoleAgentPlan({
+        paired: true,
+        groupAgentType: 'codex',
+        configuredReviewer: 'claude-code',
+        configuredArbiter: 'claude-code',
+      }),
+    ).toEqual({
+      ownerAgentType: 'codex',
+      reviewerAgentType: 'claude-code',
+      arbiterAgentType: 'claude-code',
+    });
+  });
+
+  it('collapses reviewer to owner and keeps arbiter null when absent', () => {
+    expect(
+      resolveRoleAgentPlan({
+        paired: true,
+        groupAgentType: 'claude-code',
+        configuredReviewer: 'claude-code',
+      }),
+    ).toEqual({
+      ownerAgentType: 'claude-code',
+      reviewerAgentType: 'claude-code',
+      arbiterAgentType: null,
+    });
+  });
+});