feat(kevin_bridge): main orchestrator with dependency injection

Composable: cursor/aggregator/strategy/publisher/audit_writer/broker
all injected. Master kill-switch (kevin_enable_trading=false) routes to
audit-only path. Cursor advances ONLY after XADD succeeds (race fix).
Concrete collaborators wired in subsequent tasks.

Also extends TradeSignal + SignalDirection.EXIT with the optional
fields Kevin paths need (strategy_id, target_dollars, stop_loss_pct,
take_profit_pct).

tests/services/kevin_signal_bridge/test_main.py

@@ -0,0 +1,175 @@
+"""Smoke-level orchestrator tests for the Kevin signal bridge."""
+
+from decimal import Decimal
+from unittest.mock import AsyncMock, MagicMock
+
+from services.kevin_signal_bridge.main import KevinBridge
+
+
+async def test_bridge_dry_run_writes_audit_does_not_publish():
+    """When TRADING_KEVIN_ENABLE_TRADING=false the bridge writes an audit row
+    and never calls publisher.publish."""
+    config = MagicMock(kevin_enable_trading=False, kevin_stop_loss_pct=0.08, kevin_take_profit_pct=0.20, kevin_avoid_blocks_days=7)
+    cursor = AsyncMock()
+    cursor.last_seen_id.return_value = 0
+    publisher = AsyncMock()
+    aggregator = AsyncMock()
+    aggregator.fetch_pending.return_value = [
+        MagicMock(
+            id=1,
+            symbol="NVDA",
+            action=MagicMock(value="buy"),
+            conviction=Decimal("0.8"),
+            time_horizon=MagicMock(value="weeks"),
+        ),
+    ]
+    strategy = AsyncMock()
+    strategy.evaluate_mention.return_value = MagicMock(
+        decision=MagicMock(value="open_long", name="OPEN_LONG"),
+        symbol="NVDA",
+        target_dollars=Decimal("3000"),
+        holding_days=10,
+        effective_conviction=Decimal("0.8"),
+        rationale="ok",
+    )
+    # Make the .decision attribute compare against KevinDecisionType.OPEN_LONG
+    from shared.schemas.kevin import KevinDecisionType
+    strategy.evaluate_mention.return_value.decision = KevinDecisionType.OPEN_LONG
+
+    audit_writer = AsyncMock()
+    broker = AsyncMock()
+    broker.is_asset_tradable.return_value = True
+    broker.get_latest_price.return_value = Decimal("100")
+    broker.get_account.return_value = MagicMock(
+        equity=Decimal("100000"), cash=Decimal("100000")
+    )
+    broker.get_positions.return_value = []
+
+    bridge = KevinBridge(
+        config=config,
+        cursor=cursor,
+        publisher=publisher,
+        aggregator=aggregator,
+        strategy=strategy,
+        audit_writer=audit_writer,
+        broker=broker,
+    )
+    await bridge.process_one_pass()
+
+    publisher.publish.assert_not_called()
+    audit_writer.write.assert_awaited()
+    args = audit_writer.write.call_args
+    assert "dry_run" in str(args).lower()
+
+
+async def test_bridge_kill_switch_on_publishes_to_stream():
+    config = MagicMock(
+        kevin_enable_trading=True,
+        kevin_stop_loss_pct=0.08,
+        kevin_take_profit_pct=0.20,
+        kevin_avoid_blocks_days=7,
+    )
+    cursor = AsyncMock()
+    cursor.last_seen_id.return_value = 0
+    publisher = AsyncMock()
+    publisher.publish.return_value = "1234-0"
+    aggregator = AsyncMock()
+    aggregator.fetch_pending.return_value = [
+        MagicMock(
+            id=1,
+            symbol="NVDA",
+            action=MagicMock(value="buy"),
+            conviction=Decimal("0.8"),
+            effective_conviction=Decimal("0.8"),
+            time_horizon=MagicMock(value="weeks"),
+        ),
+    ]
+    strategy = AsyncMock()
+    from shared.schemas.kevin import KevinDecisionType
+    strategy.evaluate_mention.return_value = MagicMock(
+        decision=KevinDecisionType.OPEN_LONG,
+        symbol="NVDA",
+        target_dollars=Decimal("3000"),
+        holding_days=10,
+        effective_conviction=Decimal("0.8"),
+        rationale="ok",
+    )
+    audit_writer = AsyncMock()
+    broker = AsyncMock()
+    broker.is_asset_tradable.return_value = True
+    broker.get_latest_price.return_value = Decimal("100")
+    broker.get_account.return_value = MagicMock(
+        equity=Decimal("100000"), cash=Decimal("100000")
+    )
+    broker.get_positions.return_value = []
+
+    bridge = KevinBridge(
+        config=config,
+        cursor=cursor,
+        publisher=publisher,
+        aggregator=aggregator,
+        strategy=strategy,
+        audit_writer=audit_writer,
+        broker=broker,
+    )
+    await bridge.process_one_pass()
+
+    publisher.publish.assert_awaited_once()
+    cursor.advance.assert_awaited_with(1)
+
+
+async def test_bridge_advances_cursor_only_after_publish():
+    """Race-condition guard: cursor must NOT advance if publish raises."""
+    config = MagicMock(
+        kevin_enable_trading=True,
+        kevin_stop_loss_pct=0.08,
+        kevin_take_profit_pct=0.20,
+        kevin_avoid_blocks_days=7,
+    )
+    cursor = AsyncMock()
+    cursor.last_seen_id.return_value = 0
+    publisher = AsyncMock()
+    publisher.publish.side_effect = RuntimeError("XADD failed")
+    aggregator = AsyncMock()
+    aggregator.fetch_pending.return_value = [
+        MagicMock(
+            id=1,
+            symbol="NVDA",
+            action=MagicMock(value="buy"),
+            conviction=Decimal("0.8"),
+            effective_conviction=Decimal("0.8"),
+            time_horizon=MagicMock(value="weeks"),
+        ),
+    ]
+    strategy = AsyncMock()
+    from shared.schemas.kevin import KevinDecisionType
+    strategy.evaluate_mention.return_value = MagicMock(
+        decision=KevinDecisionType.OPEN_LONG,
+        symbol="NVDA",
+        target_dollars=Decimal("3000"),
+        holding_days=10,
+        effective_conviction=Decimal("0.8"),
+        rationale="ok",
+    )
+    audit_writer = AsyncMock()
+    broker = AsyncMock()
+    broker.is_asset_tradable.return_value = True
+    broker.get_latest_price.return_value = Decimal("100")
+    broker.get_account.return_value = MagicMock(
+        equity=Decimal("100000"), cash=Decimal("100000")
+    )
+    broker.get_positions.return_value = []
+
+    bridge = KevinBridge(
+        config=config,
+        cursor=cursor,
+        publisher=publisher,
+        aggregator=aggregator,
+        strategy=strategy,
+        audit_writer=audit_writer,
+        broker=broker,
+    )
+    await bridge.process_one_pass()
+
+    # cursor.advance must NOT have been called for mention 1
+    cursor.advance.assert_not_called()