feat: transform to REST API service with SQLite persistence (v0.3.0)

Major architecture transformation from batch-only to API service with
database persistence for Windmill integration.

## REST API Implementation
- POST /simulate/trigger - Start simulation jobs
- GET /simulate/status/{job_id} - Monitor job progress
- GET /results - Query results with filters (job_id, date, model)
- GET /health - Service health checks

## Database Layer
- SQLite persistence with 6 tables (jobs, job_details, positions,
  holdings, reasoning_logs, tool_usage)
- Foreign key constraints with cascade deletes
- Replaces JSONL file storage

## Backend Components
- JobManager: Job lifecycle management with concurrency control
- RuntimeConfigManager: Thread-safe isolated runtime configs
- ModelDayExecutor: Single model-day execution engine
- SimulationWorker: Date-sequential, model-parallel orchestration

## Testing
- 102 unit and integration tests (85% coverage)
- Database: 98% coverage
- Job manager: 98% coverage
- API endpoints: 81% coverage
- Pydantic models: 100% coverage
- TDD approach throughout

## Docker Deployment
- Dual-mode: API server (persistent) + batch (one-time)
- Health checks with 30s interval
- Volume persistence for database and logs
- Separate entrypoints for each mode

## Validation Tools
- scripts/validate_docker_build.sh - Build validation
- scripts/test_api_endpoints.sh - Complete API testing
- scripts/test_batch_mode.sh - Batch mode validation
- DOCKER_API.md - Deployment guide
- TESTING_GUIDE.md - Testing procedures

## Configuration
- API_PORT environment variable (default: 8080)
- Backwards compatible with existing configs
- FastAPI, uvicorn, pydantic>=2.0 dependencies

Co-Authored-By: AI Assistant <noreply@example.com>

docker-compose.yml

@@ -1,9 +1,10 @@
 services:
-  ai-trader:
+  # Batch mode: Run one-time simulations with config file
+  ai-trader-batch:
     image: ghcr.io/xe138/ai-trader:latest
     # Uncomment to build locally instead of pulling:
     # build: .
-    container_name: ai-trader-app
+    container_name: ai-trader-batch
     volumes:
       - ${VOLUME_PATH:-.}/data:/app/data
       - ${VOLUME_PATH:-.}/logs:/app/logs
@@ -35,4 +36,58 @@ services:
       - "${TRADE_HTTP_PORT:-8002}:8002"
       - "${GETPRICE_HTTP_PORT:-8003}:8003"
       - "${WEB_HTTP_PORT:-8888}:8888"
-    restart: on-failure:3  # Restart max 3 times on failure, prevents endless loops
+    restart: "no"  # Batch jobs should not auto-restart
+    profiles:
+      - batch  # Only start with: docker-compose --profile batch up
+
+  # API mode: REST API server for Windmill integration
+  ai-trader-api:
+    image: ghcr.io/xe138/ai-trader:latest
+    # Uncomment to build locally instead of pulling:
+    # build: .
+    container_name: ai-trader-api
+    entrypoint: ["./entrypoint-api.sh"]
+    volumes:
+      - ${VOLUME_PATH:-.}/data:/app/data
+      - ${VOLUME_PATH:-.}/logs:/app/logs
+      - ${VOLUME_PATH:-.}/configs:/app/configs
+    environment:
+      # AI Model API Configuration
+      - OPENAI_API_BASE=${OPENAI_API_BASE}
+      - OPENAI_API_KEY=${OPENAI_API_KEY}
+
+      # Data Source Configuration
+      - ALPHAADVANTAGE_API_KEY=${ALPHAADVANTAGE_API_KEY}
+      - JINA_API_KEY=${JINA_API_KEY}
+
+      # System Configuration
+      - RUNTIME_ENV_PATH=/app/data/runtime_env.json
+
+      # MCP Service Ports (fixed internally)
+      - MATH_HTTP_PORT=8000
+      - SEARCH_HTTP_PORT=8001
+      - TRADE_HTTP_PORT=8002
+      - GETPRICE_HTTP_PORT=8003
+
+      # API Configuration
+      - API_PORT=${API_PORT:-8080}
+
+      # Agent Configuration
+      - AGENT_MAX_STEP=${AGENT_MAX_STEP:-30}
+    ports:
+      # MCP service ports (internal)
+      - "${MATH_HTTP_PORT:-8000}:8000"
+      - "${SEARCH_HTTP_PORT:-8001}:8001"
+      - "${TRADE_HTTP_PORT:-8002}:8002"
+      - "${GETPRICE_HTTP_PORT:-8003}:8003"
+      # API server port (primary interface)
+      - "${API_PORT:-8080}:8080"
+      # Web dashboard
+      - "${WEB_HTTP_PORT:-8888}:8888"
+    restart: unless-stopped  # Keep API server running
+    healthcheck:
+      test: ["CMD", "curl", "-f", "http://localhost:8080/health"]
+      interval: 30s
+      timeout: 10s
+      retries: 3
+      start_period: 40s