fix: Fix trading precision issues and improve error handling

- Fix quantity precision calculation for Binance, OKX, Bybit, Bitget, Deepcoin exchanges
- Improve OpenRouter API error handling with detailed error messages
- Add SECRET_KEY validation in Docker deployment entrypoint
- Fix K-line chart measurement tool click issue
- Adapt billing page text colors for dark theme
- Update frontend build files

backend_api_python/docker-entrypoint.sh

@@ -0,0 +1,84 @@
+#!/bin/bash
+# QuantDinger Docker Entrypoint Script
+# Checks and validates SECRET_KEY before starting the application
+
+set -e
+
+echo "============================================"
+echo "  QuantDinger Backend - Starting..."
+echo "============================================"
+
+# Check if .env file exists
+if [ ! -f /app/.env ]; then
+    echo "[WARNING] .env file not found at /app/.env"
+    echo "Creating .env from env.example..."
+    if [ -f /app/env.example ]; then
+        cp /app/env.example /app/.env
+        echo "[INFO] Created .env from env.example"
+        echo "[IMPORTANT] Please edit /app/.env and set a secure SECRET_KEY before restarting!"
+    else
+        echo "[ERROR] env.example not found. Cannot create .env automatically."
+        exit 1
+    fi
+fi
+
+# Check SECRET_KEY configuration
+DEFAULT_SECRET="quantdinger-secret-key-change-me"
+CURRENT_SECRET=$(grep -E "^SECRET_KEY=" /app/.env 2>/dev/null | cut -d'=' -f2- | tr -d '"' | tr -d "'" | xargs || echo "")
+
+if [ -z "$CURRENT_SECRET" ]; then
+    echo ""
+    echo "============================================"
+    echo "  [SECURITY WARNING]"
+    echo "============================================"
+    echo "SECRET_KEY is not set in /app/.env"
+    echo ""
+    echo "Please set a secure SECRET_KEY before starting:"
+    echo ""
+    echo "  Option 1: Generate a random key:"
+    echo "    docker exec -it quantdinger-backend python -c \"import secrets; print(secrets.token_hex(32))\""
+    echo ""
+    echo "  Option 2: Edit .env file:"
+    echo "    SECRET_KEY=your-generated-secret-key-here"
+    echo ""
+    echo "Then restart the container:"
+    echo "    docker-compose restart backend"
+    echo ""
+    echo "============================================"
+    exit 1
+fi
+
+# Check if using default secret key
+if [ "$CURRENT_SECRET" = "$DEFAULT_SECRET" ]; then
+    echo ""
+    echo "============================================"
+    echo "  [SECURITY ERROR]"
+    echo "============================================"
+    echo "SECRET_KEY is using the default example value!"
+    echo "This is INSECURE and MUST be changed before running in production."
+    echo ""
+    echo "Current value: $CURRENT_SECRET"
+    echo ""
+    echo "To fix this:"
+    echo ""
+    echo "  1. Generate a secure random key:"
+    echo "     docker exec -it quantdinger-backend python -c \"import secrets; print(secrets.token_hex(32))\""
+    echo ""
+    echo "  2. Edit backend_api_python/.env and replace SECRET_KEY:"
+    echo "     SECRET_KEY=<generated-key-here>"
+    echo ""
+    echo "  3. Restart the container:"
+    echo "     docker-compose restart backend"
+    echo ""
+    echo "Or use this one-liner (Linux/Mac):"
+    echo "     sed -i 's|SECRET_KEY=.*|SECRET_KEY='\$(python3 -c \"import secrets; print(secrets.token_hex(32))\")\'|' backend_api_python/.env"
+    echo ""
+    echo "============================================"
+    exit 1
+fi
+
+echo "[OK] SECRET_KEY is configured"
+echo ""
+
+# Start the application
+exec "$@"