Fix API endpoint configuration with environment-aware URLs

- Add environment-based API URL configuration (dev: localhost:8000, prod: api.pennyzo.com)
- Update PennyzoApiService to use centralized config with timeout settings
- Fix API status checker scripts to load .env variables using dotenv
- Add environment management scripts (set-env.ps1) with npm shortcuts
- Create comprehensive configuration testing and validation tools
- Add TypeScript definitions for Vite environment variables
- Update all documentation with new environment configuration instructions
- Install dotenv package for Node.js environment variable loading
- All APIs now correctly use environment-appropriate URLs automatically

.env.example

@@ -1,2 +1,31 @@
-# API base URL (override default production URL if needed)
+# Environment Configuration Example
+# Copy this file to .env and update the values as needed
+
+# API Base URL - Choose based on your environment
+# Development (default)
+VITE_API_BASE_URL=http://localhost:8000
+
+# Production
 # VITE_API_BASE_URL=https://api.pennyzo.com/api/v1/general
+
+# Backend API Configuration (for reference)
+API_PORT=8000
+API_HOST=localhost
+
+# Environment
+NODE_ENV=development
+
+# Debug settings
+DEBUG=true
+LOG_LEVEL=INFO
+
+# API Status Checker Credentials (optional - for testing authenticated endpoints)
+# PENNYZO_TEST_EMAIL=your-test-email@example.com
+# PENNYZO_TEST_PASSWORD=your-test-password
+
+# CORS Settings (for reference - these are backend settings)
+# The following origins are typically allowed in development:
+# - http://localhost:3000 (React default)
+# - http://127.0.0.1:3000
+# - http://localhost:5173 (Vite default)
+# - http://127.0.0.1:5173