feat: auto-initialize trading_days schema on database creation

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

tests/integration/test_database_initialization.py

@@ -0,0 +1,30 @@
+import pytest
+from api.database import Database
+
+
+class TestDatabaseInitialization:
+
+    def test_database_creates_new_schema_on_init(self, tmp_path):
+        """Test database automatically creates trading_days schema."""
+        db_path = tmp_path / "new.db"
+
+        # Create database (should auto-initialize schema)
+        db = Database(str(db_path))
+
+        # Verify trading_days table exists
+        cursor = db.connection.execute(
+            "SELECT name FROM sqlite_master WHERE type='table' AND name='trading_days'"
+        )
+        assert cursor.fetchone() is not None
+
+        # Verify holdings table exists
+        cursor = db.connection.execute(
+            "SELECT name FROM sqlite_master WHERE type='table' AND name='holdings'"
+        )
+        assert cursor.fetchone() is not None
+
+        # Verify actions table exists
+        cursor = db.connection.execute(
+            "SELECT name FROM sqlite_master WHERE type='table' AND name='actions'"
+        )
+        assert cursor.fetchone() is not None