Require explicit commenter context in openers

tests/openrouter-client.test.ts

@@ -669,6 +669,7 @@ describe('OpenRouterClient', () => {
       const userPrompt = mockCreate.mock.calls[0][0].messages[1].content as string;
       expect(systemPrompt).toContain('The RECIPIENT is the commenter');
       expect(systemPrompt).toContain('The SOURCE POST SUBJECT is a different person');
+      expect(systemPrompt).toContain('The first sentence MUST explicitly anchor to the public comment');
       expect(userPrompt).toContain('I want that too');
       expect(`${systemPrompt}\n${userPrompt}`).not.toContain('Write a message for Commenter about');
     });