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

scripts/generate-secret-key.ps1

@@ -0,0 +1,31 @@
+# Helper script to generate a secure SECRET_KEY for QuantDinger (Windows PowerShell)
+# Usage: .\scripts\generate-secret-key.ps1
+
+$envFile = "backend_api_python\.env"
+
+# Check if .env exists
+if (-not (Test-Path $envFile)) {
+    Write-Host "Error: $envFile not found" -ForegroundColor Red
+    Write-Host "Please run: Copy-Item backend_api_python\env.example -Destination backend_api_python\.env"
+    exit 1
+}
+
+# Generate a secure random key
+$newKey = python -c "import secrets; print(secrets.token_hex(32))"
+
+if ($LASTEXITCODE -ne 0) {
+    Write-Host "Error: Failed to generate SECRET_KEY. Make sure Python is installed." -ForegroundColor Red
+    exit 1
+}
+
+# Update SECRET_KEY in .env file
+$content = Get-Content $envFile
+$content = $content -replace '^SECRET_KEY=.*', "SECRET_KEY=$newKey"
+$content | Set-Content $envFile
+
+Write-Host "✅ SECRET_KEY generated and updated in $envFile" -ForegroundColor Green
+Write-Host ""
+Write-Host "Generated key: $newKey" -ForegroundColor Cyan
+Write-Host ""
+Write-Host "You can now start the application:"
+Write-Host "  docker-compose up -d --build"

scripts/generate-secret-key.sh

@@ -0,0 +1,33 @@
+#!/bin/bash
+# Helper script to generate a secure SECRET_KEY for QuantDinger
+# Usage: ./scripts/generate-secret-key.sh
+
+set -e
+
+ENV_FILE="backend_api_python/.env"
+
+# Check if .env exists
+if [ ! -f "$ENV_FILE" ]; then
+    echo "Error: $ENV_FILE not found"
+    echo "Please run: cp backend_api_python/env.example backend_api_python/.env"
+    exit 1
+fi
+
+# Generate a secure random key
+NEW_KEY=$(python3 -c "import secrets; print(secrets.token_hex(32))")
+
+# Update SECRET_KEY in .env file
+if [[ "$OSTYPE" == "darwin"* ]]; then
+    # macOS
+    sed -i '' "s|^SECRET_KEY=.*|SECRET_KEY=$NEW_KEY|" "$ENV_FILE"
+else
+    # Linux
+    sed -i "s|^SECRET_KEY=.*|SECRET_KEY=$NEW_KEY|" "$ENV_FILE"
+fi
+
+echo "✅ SECRET_KEY generated and updated in $ENV_FILE"
+echo ""
+echo "Generated key: $NEW_KEY"
+echo ""
+echo "You can now start the application:"
+echo "  docker-compose up -d --build"