fix(compression): suppress per-output debug logs for not_applied decision reason

Add 'not_applied' to _NOISY_NOOP_DECISION_REASONS to eliminate debug log
spam when compression pipeline runs but doesn't modify content. This is the
normal path for outputs that don't match any rule or are below thresholds.

Author: Mateusz

src/core/services/tool_output_compression_service.py

@@ -69,6 +69,7 @@
 _NOISY_NOOP_DECISION_REASONS = frozenset(
     {
         "already_processed_output",
+        "not_applied",
         "compression_disabled",
         "below_min_bytes",
         "category_disabled",

tests/unit/core/services/test_tool_output_compression_service.py

@@ -761,20 +761,9 @@ async def test_service_logs_debug_for_evaluated_non_applied_output(
 
     assert result.records[0].applied is False
     assert result.records[0].failed_open is False
+    # Suppressed to reduce log noise: not_applied is now in _NOISY_NOOP_DECISION_REASONS
     assert len(capture_logger.info_calls) == 0
-    assert len(capture_logger.debug_calls) == 1
-    _, metadata = capture_logger.debug_calls[0]
-    assert metadata["decision_reason"] == "not_applied"
-    assert metadata["tool_name"] == "shell"
-    assert metadata["tool_category"] == "command_execution"
-    assert metadata["bytes_in"] == 4
-    assert metadata["bytes_out"] == 4
-    assert metadata["methods_attempted"] == ["inflate"]
-    assert metadata["methods_applied"] == []
-    assert metadata["failed_open"] is False
-    assert metadata["applied"] is False
-    assert "content" not in metadata
-    assert "payload" not in metadata
+    assert len(capture_logger.debug_calls) == 0
 
 
 @pytest.mark.asyncio