fix: address PR #434 code-quality review findings

- add_decision: pass valid_from/valid_until through kwargs path so
  temporal bounds are not silently dropped into metadata (Codex P1)
- add_decision: raise ValueError when Decision object and kwargs are
  both provided, instead of silently ignoring the kwargs (Codex P2)
- fix guard condition to exclude decision_maker (non-None default)
  to avoid false-positive ValueError on plain add_decision(obj) calls
- test_395: remove unused `import time`; strengthen as_of test with
  concrete assertions on scenarios list (github-code-quality)
- test_unreleased: remove unused `import time`; drop unused `snap =`
  assignment; drop unused `provider =` assignment (github-code-quality)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/test_395_temporal_semantics_comprehensive.py

@@ -17,7 +17,6 @@ Already covered separately:
 
 from __future__ import annotations
 
-import time
 from datetime import datetime, timezone
 from unittest.mock import MagicMock
 
@@ -1062,6 +1061,8 @@ class TestFindPrecedentsAsOf:
         # Bob's decision should be reachable; Alice's should not appear
         # (implementation may not filter on valid_from, just check it doesn't crash)
         assert isinstance(precedents, list)
+        assert "approve loan for Bob" in scenarios
+        assert "approve loan for Alice" not in scenarios
 
     def test_find_precedents_no_as_of_returns_list(self):
         self.graph.record_decision(

tests/test_unreleased_changelog_comprehensive.py

@@ -19,7 +19,6 @@ Covers gaps not addressed by existing test files:
 from __future__ import annotations
 
 import threading
-import time
 from datetime import datetime, timezone
 from unittest.mock import MagicMock, patch
 
@@ -292,7 +291,7 @@ class TestNamedTagsAdditional:
         graph = ContextGraph()
         manager = TemporalVersionManager()
         graph.add_node("n1", "entity")
-        snap = manager.create_snapshot(
+        manager.create_snapshot(
             graph.to_dict(),
             version_label="v1.0",
             author="user@example.com",
@@ -873,7 +872,7 @@ class TestOllamaProviderBaseURLGap:
         ollama_mock.Client = MagicMock(return_value=MagicMock())
         with patch.dict("sys.modules", {"ollama": ollama_mock}):
             from semantica.semantic_extract.providers import OllamaProvider
-            provider = OllamaProvider(
+            OllamaProvider(
                 model_name="llama3",
                 base_url="http://192.168.1.10:11434",
             )