fix: resolve ruff lint errors in Phase 2 code

- Move intent imports to TYPE_CHECKING block in graph.py (TC001)
- Rename test classes to CapWords convention (N801)
- Fix line length violations across test files (E501)
- Auto-fix import sorting (I001)

backend/tests/integration/test_routing.py

@@ -24,7 +24,6 @@ from app.registry import AgentConfig
 from app.session_manager import SessionManager
 from app.ws_handler import dispatch_message
 
-
 # ---------------------------------------------------------------------------
 # Helpers
 # ---------------------------------------------------------------------------
@@ -78,10 +77,22 @@ def _state(*, interrupt: bool = False, data: dict | None = None):
 
 
 AGENTS = (
-    AgentConfig(name="order_lookup", description="Looks up orders", permission="read", tools=["get_order_status", "get_tracking_info"]),
-    AgentConfig(name="order_actions", description="Modifies orders", permission="write", tools=["cancel_order"]),
-    AgentConfig(name="discount", description="Applies discounts", permission="write", tools=["apply_discount", "generate_coupon"]),
-    AgentConfig(name="fallback", description="Handles unclear requests", permission="read", tools=["fallback_respond"]),
+    AgentConfig(
+        name="order_lookup", description="Looks up orders",
+        permission="read", tools=["get_order_status", "get_tracking_info"],
+    ),
+    AgentConfig(
+        name="order_actions", description="Modifies orders",
+        permission="write", tools=["cancel_order"],
+    ),
+    AgentConfig(
+        name="discount", description="Applies discounts",
+        permission="write", tools=["apply_discount", "generate_coupon"],
+    ),
+    AgentConfig(
+        name="fallback", description="Handles unclear requests",
+        permission="read", tools=["fallback_respond"],
+    ),
 )
 
 
@@ -136,7 +147,9 @@ class TestSingleIntentRouting:
     @pytest.mark.asyncio
     async def test_routes_to_order_lookup(self) -> None:
         result = ClassificationResult(
-            intents=(IntentTarget(agent_name="order_lookup", confidence=0.95, reasoning="status query"),),
+            intents=(IntentTarget(
+                agent_name="order_lookup", confidence=0.95, reasoning="status query",
+            ),),
         )
         graph = _make_graph(result, [
             _tool_chunk("get_order_status", {"order_id": "1042"}, "order_lookup"),