fix: add summary fallback and stabilize recording sink

tests/test_openrouter_client.py

@@ -13,6 +13,7 @@ from openrouter_client import (
     TRANSCRIPTION_MODELS,
     _audio_format,
     _build_transcription_payload,
+    _chat_completion,
     _chunk_text,
     _combined_summary_prompt,
     _summary_prompt,
@@ -182,3 +183,46 @@ def test_transcribe_chunk_reports_provider_fallback_when_all_providers_fail(tmp_
     assert "Transcription failed across providers" in message
     assert "OpenRouter transcription failed" in message
     assert "direct OpenAI fallback skipped" in message
+
+
+def test_chat_completion_falls_back_to_direct_openai_when_openrouter_returns_empty(monkeypatch):
+    calls = []
+
+    async def fake_openrouter(prompt: str, *, timeout: int = 180) -> str:
+        calls.append(("openrouter", prompt, timeout))
+        raise RuntimeError("OpenRouter summarization returned empty content")
+
+    async def fake_openai(prompt: str, *, timeout: int = 180) -> str:
+        calls.append(("openai", prompt, timeout))
+        return "direct summary"
+
+    monkeypatch.setattr(openrouter_client, "_chat_completion_openrouter", fake_openrouter)
+    monkeypatch.setattr(openrouter_client, "_chat_completion_openai", fake_openai)
+    monkeypatch.setattr(openrouter_client, "_openai_api_key", lambda: "sk-test")
+
+    result = asyncio.run(_chat_completion("summarize this", timeout=42))
+
+    assert result == "direct summary"
+    assert calls == [
+        ("openrouter", "summarize this", 42),
+        ("openai", "summarize this", 42),
+    ]
+
+
+def test_chat_completion_reports_provider_fallback_when_all_summarizers_fail(monkeypatch):
+    async def fake_openrouter(_prompt: str, *, timeout: int = 180) -> str:
+        raise RuntimeError("OpenRouter summarization returned empty content")
+
+    monkeypatch.setattr(openrouter_client, "_chat_completion_openrouter", fake_openrouter)
+    monkeypatch.setattr(openrouter_client, "_openai_api_key", lambda: "")
+
+    try:
+        asyncio.run(_chat_completion("summarize this"))
+    except RuntimeError as exc:
+        message = str(exc)
+    else:
+        raise AssertionError("Expected summarization failure")
+
+    assert "Summarization failed across providers" in message
+    assert "OpenRouter summarization returned empty content" in message
+    assert "direct OpenAI summarization fallback skipped" in message