fix: initialize dev database on API startup to prevent stale job blocking

- Add database initialization to API lifespan event handler
- DEV mode: Reset database on startup (unless PRESERVE_DEV_DATA=true)
- PROD mode: Ensure database schema exists
- Migrate from deprecated @app.on_event to modern lifespan context manager
- Fixes 400 error "Another simulation job is already running" on fresh container starts

This ensures the dev database is reset when the API server starts in dev mode,
preventing stale "running" or "pending" jobs from blocking new job creation.

api/main.py

@@ -17,6 +17,7 @@ from pathlib import Path
 from fastapi import FastAPI, HTTPException, Query
 from fastapi.responses import JSONResponse
 from pydantic import BaseModel, Field, field_validator
+from contextlib import asynccontextmanager
 
 from api.job_manager import JobManager
 from api.simulation_worker import SimulationWorker
@@ -127,21 +128,38 @@ def create_app(
     Returns:
         Configured FastAPI app
     """
+    @asynccontextmanager
+    async def lifespan(app: FastAPI):
+        """Initialize database on startup, cleanup on shutdown if needed"""
+        from tools.deployment_config import is_dev_mode, get_db_path
+        from api.database import initialize_dev_database, initialize_database
+
+        # Startup
+        if is_dev_mode():
+            # Initialize dev database (reset unless PRESERVE_DEV_DATA=true)
+            dev_db_path = get_db_path(app.state.db_path)
+            initialize_dev_database(dev_db_path)
+            log_dev_mode_startup_warning()
+        else:
+            # Ensure production database schema exists
+            initialize_database(app.state.db_path)
+
+        yield
+
+        # Shutdown (if needed in future)
+        pass
+
     app = FastAPI(
         title="AI-Trader Simulation API",
         description="REST API for triggering and monitoring AI trading simulations",
-        version="1.0.0"
+        version="1.0.0",
+        lifespan=lifespan
     )
 
     # Store paths in app state
     app.state.db_path = db_path
     app.state.config_path = config_path
 
-    @app.on_event("startup")
-    async def startup_event():
-        """Display DEV mode warning on startup if applicable"""
-        log_dev_mode_startup_warning()
-
     @app.post("/simulate/trigger", response_model=SimulateTriggerResponse, status_code=200)
     async def trigger_simulation(request: SimulateTriggerRequest):
         """
@@ -500,7 +518,7 @@ app = create_app()
 if __name__ == "__main__":
     import uvicorn
 
-    # Display DEV mode warning if applicable
-    log_dev_mode_startup_warning()
+    # Note: Database initialization happens in startup_event()
+    # DEV mode warning will be displayed there as well
 
     uvicorn.run(app, host="0.0.0.0", port=8080)