feat: implement ERP AI Assistant Phase 1

Backend (FastAPI + SQLAlchemy + Claude API + RAG):
- Config management with Pydantic v2
- Database engine with connection pooling and SQL injection prevention
- AI engine with Claude API integration (support custom base URL)
- RAG engine with ChromaDB and sentence-transformers
- Requirement analysis service
- Config generation service
- Executor engine with SQL validation
- REST API endpoints: /analyze, /generate, /execute

Frontend (Vue 3 + Element Plus + Pinia):
- Complete 3-step workflow: analyze → generate → execute
- Step indicator with progress visualization
- Analysis result display with field table
- SQL preview with monospace font
- Execute confirmation dialog with safety warning
- Execution result display
- State management with Pinia
- API service integration

Security:
- SQL injection prevention with parameterized queries
- Dangerous SQL operation blocking
- Database password URL encoding
- Transaction auto-rollback
- Pydantic config validation

Features:
- Natural language requirement analysis
- Automated SQL configuration generation
- Safe execution with human review
- LAN access support
- Custom Claude API endpoint support

Documentation:
- README with quick start guide
- Quick start guide
- LAN access configuration
- Dependency fixes guide
- Claude API configuration
- Git operation guide
- Implementation report

Dependencies fixed:
- numpy<2.0.0 for chromadb compatibility
- sentence-transformers==2.7.0 for huggingface_hub compatibility

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/main.py

@@ -0,0 +1,78 @@
+"""FastAPI application entry point for ERP AI Assistant.
+
+This module creates and configures the main FastAPI application instance.
+"""
+
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.config import get_settings
+from app.api import analyze, generate, execute
+
+# Get application settings
+settings = get_settings()
+
+# Create FastAPI application instance
+app = FastAPI(
+    title=settings.APP_NAME,
+    version="1.0.0",
+    debug=settings.DEBUG,
+    description="AI-powered assistant for ERP platform configuration"
+)
+
+# Configure CORS middleware for frontend communication
+# For development: allow all origins with port 5173
+# For production: configure specific origins in environment
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"] if settings.DEBUG else [
+        "http://localhost:5173",
+        "http://127.0.0.1:5173",
+    ],
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# Register API routers
+app.include_router(analyze.router, prefix="/api/v1", tags=["Analysis"])
+app.include_router(generate.router, prefix="/api/v1", tags=["Generation"])
+app.include_router(execute.router, prefix="/api/v1", tags=["Execution"])
+
+
+@app.get("/", tags=["Root"])
+async def root() -> dict:
+    """Root endpoint returning application info.
+
+    Returns:
+        Dictionary with application name, version, and status
+    """
+    return {
+        "message": settings.APP_NAME,
+        "version": "1.0.0",
+        "status": "running"
+    }
+
+
+@app.get("/health", tags=["Health"])
+async def health_check() -> dict:
+    """Health check endpoint for monitoring.
+
+    Returns:
+        Dictionary with health status
+    """
+    return {
+        "status": "healthy",
+        "version": "1.0.0"
+    }
+
+
+if __name__ == "__main__":
+    import uvicorn
+
+    uvicorn.run(
+        "app.main:app",
+        host="0.0.0.0",
+        port=8000,
+        reload=settings.DEBUG
+    )