Add complete Ouroboros trading system with TDD test suite

Implement the full autonomous trading agent architecture:
- KIS broker with async API, token refresh, leaky bucket rate limiter, and hash key signing
- Gemini-powered decision engine with JSON parsing and confidence threshold enforcement
- Risk manager with circuit breaker (-3% P&L) and fat finger protection (30% cap)
- Evolution engine for self-improving strategy generation via failure analysis
- 35 passing tests written TDD-first covering risk, broker, and brain modules
- CI/CD pipeline, Docker multi-stage build, and AI agent context docs

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tests/test_risk.py

@@ -0,0 +1,132 @@
+"""TDD tests for core/risk_manager.py — written BEFORE implementation."""
+
+from __future__ import annotations
+
+import pytest
+
+from src.core.risk_manager import (
+    CircuitBreakerTripped,
+    FatFingerRejected,
+    RiskManager,
+)
+
+
+# ---------------------------------------------------------------------------
+# Circuit Breaker Tests
+# ---------------------------------------------------------------------------
+
+
+class TestCircuitBreaker:
+    """The circuit breaker must halt all trading when daily loss exceeds the threshold."""
+
+    def test_allows_trading_when_pnl_is_positive(self, settings):
+        rm = RiskManager(settings)
+        # 2% gain — should be fine
+        rm.check_circuit_breaker(current_pnl_pct=2.0)
+
+    def test_allows_trading_at_zero_pnl(self, settings):
+        rm = RiskManager(settings)
+        rm.check_circuit_breaker(current_pnl_pct=0.0)
+
+    def test_allows_trading_at_exactly_threshold(self, settings):
+        rm = RiskManager(settings)
+        # Exactly -3.0% is ON the boundary — still allowed
+        rm.check_circuit_breaker(current_pnl_pct=-3.0)
+
+    def test_trips_when_loss_exceeds_threshold(self, settings):
+        rm = RiskManager(settings)
+        with pytest.raises(CircuitBreakerTripped):
+            rm.check_circuit_breaker(current_pnl_pct=-3.01)
+
+    def test_trips_at_large_loss(self, settings):
+        rm = RiskManager(settings)
+        with pytest.raises(CircuitBreakerTripped):
+            rm.check_circuit_breaker(current_pnl_pct=-10.0)
+
+    def test_custom_threshold(self):
+        """A stricter threshold (-1.5%) should trip earlier."""
+        from src.config import Settings
+
+        strict = Settings(
+            KIS_APP_KEY="k",
+            KIS_APP_SECRET="s",
+            KIS_ACCOUNT_NO="00000000-00",
+            KIS_BASE_URL="https://example.com",
+            GEMINI_API_KEY="g",
+            CIRCUIT_BREAKER_PCT=-1.5,
+            FAT_FINGER_PCT=30.0,
+            CONFIDENCE_THRESHOLD=80,
+            DB_PATH=":memory:",
+        )
+        rm = RiskManager(strict)
+        with pytest.raises(CircuitBreakerTripped):
+            rm.check_circuit_breaker(current_pnl_pct=-1.51)
+
+
+# ---------------------------------------------------------------------------
+# Fat Finger Tests
+# ---------------------------------------------------------------------------
+
+
+class TestFatFingerCheck:
+    """Orders exceeding 30% of total cash must be rejected."""
+
+    def test_allows_small_order(self, settings):
+        rm = RiskManager(settings)
+        # 10% of 10_000_000 = 1_000_000
+        rm.check_fat_finger(order_amount=1_000_000, total_cash=10_000_000)
+
+    def test_allows_order_at_exactly_threshold(self, settings):
+        rm = RiskManager(settings)
+        # Exactly 30% — allowed
+        rm.check_fat_finger(order_amount=3_000_000, total_cash=10_000_000)
+
+    def test_rejects_order_exceeding_threshold(self, settings):
+        rm = RiskManager(settings)
+        with pytest.raises(FatFingerRejected):
+            rm.check_fat_finger(order_amount=3_000_001, total_cash=10_000_000)
+
+    def test_rejects_massive_order(self, settings):
+        rm = RiskManager(settings)
+        with pytest.raises(FatFingerRejected):
+            rm.check_fat_finger(order_amount=9_000_000, total_cash=10_000_000)
+
+    def test_zero_cash_rejects_any_order(self, settings):
+        rm = RiskManager(settings)
+        with pytest.raises(FatFingerRejected):
+            rm.check_fat_finger(order_amount=1, total_cash=0)
+
+
+# ---------------------------------------------------------------------------
+# Pre-Order Validation (Integration of both checks)
+# ---------------------------------------------------------------------------
+
+
+class TestPreOrderValidation:
+    """validate_order must run BOTH checks before approving."""
+
+    def test_passes_when_both_checks_ok(self, settings):
+        rm = RiskManager(settings)
+        rm.validate_order(
+            current_pnl_pct=0.5,
+            order_amount=1_000_000,
+            total_cash=10_000_000,
+        )
+
+    def test_fails_on_circuit_breaker(self, settings):
+        rm = RiskManager(settings)
+        with pytest.raises(CircuitBreakerTripped):
+            rm.validate_order(
+                current_pnl_pct=-5.0,
+                order_amount=100,
+                total_cash=10_000_000,
+            )
+
+    def test_fails_on_fat_finger(self, settings):
+        rm = RiskManager(settings)
+        with pytest.raises(FatFingerRejected):
+            rm.validate_order(
+                current_pnl_pct=1.0,
+                order_amount=5_000_000,
+                total_cash=10_000_000,
+            )