test(agent): fix lazy-init rebase test fallout (#32221)

(cherry picked from commit 920013f8d9300f66276808bc945789011cdb396f)

tests/agent/test_compress_focus.py

@@ -18,6 +18,7 @@ def _make_compressor():
     compressor.context_length = 200000
     compressor.threshold_percent = 0.80
     compressor.threshold_tokens = 160000
+    compressor.summary_target_ratio = 0.20
     compressor.max_summary_tokens = 10000
     compressor.quiet_mode = True
     compressor.compression_count = 0

tests/agent/test_context_compressor.py

@@ -1788,7 +1788,8 @@ class TestSummaryFailureTrackingForGatewayWarning:
         fallback = next(m["content"] for m in result if "Summary generation was unavailable" in m.get("content", ""))
         assert len(fallback) <= 8300
         assert "deterministic fallback" in fallback
-        assert "important detail" in fallback
+        assert "1 compacted message(s)" in fallback
+        assert "ASSISTANT: head assistant" in fallback
 
     def test_compress_clears_fallback_flag_on_subsequent_success(self):
         mock_response = MagicMock()