refactor(graph): settle past decisions in graph/settlement.py

- resolve_benchmark, fetch_returns and settle_pending are module functions; the graph's settle_pending runs them under its config
- create_run_state settles through settle_pending, so the CLI path also settles under the graph's config

tests/test_portfolio_context.py

@@ -86,7 +86,7 @@ def _bare_graph(tmp_path):
     graph.memory_log = TradingMemoryLog(graph.config)
     graph.propagator = Propagator()
     graph.selected_analysts = ["market"]
-    graph._resolve_pending_entries = lambda t: None
+    graph.settle_pending = lambda t: None
     graph.resolve_instrument_context = lambda t, a="stock", d=None: ""
     graph._memory_as_of = lambda d: None
     return graph