style(server): fix ruff format violations in langgraph platform step definitions and robot helper

Applied ruff format auto-fix to resolve line-length formatting violations in:
- features/steps/langgraph_platform_remote_graph_steps.py
- robot/helper_langgraph_platform_integration.py

These files had multi-line assert statements that ruff format collapses to
single lines when they fit within the line length limit.

ISSUES CLOSED: #693

robot/helper_langgraph_platform_integration.py

@@ -62,17 +62,13 @@ def manager_not_configured() -> None:
 
     try:
         manager.list_graphs()
-        raise AssertionError(
-            "Expected RemoteGraphNotAvailableError from list_graphs"
-        )
+        raise AssertionError("Expected RemoteGraphNotAvailableError from list_graphs")
     except RemoteGraphNotAvailableError:
         pass
 
     try:
         manager.invoke("test-actor", {})
-        raise AssertionError(
-            "Expected RemoteGraphNotAvailableError from invoke"
-        )
+        raise AssertionError("Expected RemoteGraphNotAvailableError from invoke")
     except RemoteGraphNotAvailableError:
         pass
 
@@ -234,9 +230,7 @@ def postgresql_config() -> None:
     assert config.database == "cleveragents", (
         f"Expected database='cleveragents', got {config.database!r}"
     )
-    assert config.username == "app", (
-        f"Expected username='app', got {config.username!r}"
-    )
+    assert config.username == "app", f"Expected username='app', got {config.username!r}"
     assert config.port == 5432, f"Expected port=5432, got {config.port}"
     assert config.ssl_mode == "prefer", (
         f"Expected ssl_mode='prefer', got {config.ssl_mode!r}"
@@ -251,12 +245,8 @@ def postgresql_config() -> None:
     assert async_url.startswith("postgresql+asyncpg://"), (
         f"Expected async URL to start with 'postgresql+asyncpg://', got {async_url!r}"
     )
-    assert "db.example.com" in async_url, (
-        f"Expected host in URL, got {async_url!r}"
-    )
-    assert "cleveragents" in async_url, (
-        f"Expected database in URL, got {async_url!r}"
-    )
+    assert "db.example.com" in async_url, f"Expected host in URL, got {async_url!r}"
+    assert "cleveragents" in async_url, f"Expected database in URL, got {async_url!r}"
 
     # Sync URL
     sync_url = config.to_url(async_driver=False)