feat(signal_v2-phase4-task3): integrate signal_generator into poll_loop

poll_loop now accepts dedup + settings kwargs (backwards-compatible defaults).
After each in-window cycle (stock pull + minute momentum + optional post-close),
generate_signals is called to populate state.signals for downstream Phase 5
pickup. main.py lifespan wires _ctx.dedup + settings into the poll_loop task.

1 integration test added (anomaly-free stop_loss path via direct generate_signals
call, exercises the same code path that poll_loop runs).

56 tests pass.

signal_v2/main.py

@@ -82,6 +82,8 @@ async def lifespan(app: FastAPI):
             _ctx.client, state_mod.state, _ctx.shutdown,
             kis_client=_ctx.kis_client,
             chronos=_ctx.chronos,
+            dedup=_ctx.dedup,
+            settings=settings,
         )
     )