fix: CI failures — update workflow for uv migration, fix lint and format

- Switch CI install step from `pip install -r requirements.txt` to
  `pip install -e ".[dev]"` since requirements.txt was removed
- Add noqa: E402 to intentionally-late imports in conftest.py
  (HOME must be isolated before mempalace imports)
- Remove unused KnowledgeGraph import in test_knowledge_graph.py
- Apply ruff formatting to test files

tests/test_searcher.py

@@ -24,10 +24,7 @@ class TestSearchMemories:
 
     def test_wing_and_room_filter(self, palace_path, seeded_collection):
         result = search_memories("code", palace_path, wing="project", room="frontend")
-        assert all(
-            r["wing"] == "project" and r["room"] == "frontend"
-            for r in result["results"]
-        )
+        assert all(r["wing"] == "project" and r["room"] == "frontend" for r in result["results"])
 
     def test_n_results_limit(self, palace_path, seeded_collection):
         result = search_memories("code", palace_path, n_results=2)