feat: add EdgeOne Pages as AI provider

[zhoujie0531]

Summary

Add EdgeOne Pages as a new AI provider option, enabling users to use EdgeOne's Edge AI service with DeepSeek models without requiring an API key.

Changes

• Add EdgeOne provider option in model selector and configuration
• Implement OpenAI-compatible Edge Function (/api/edgeai/chat/completions) for EdgeOne Pages
• Support DeepSeek models: deepseek-v3.2
• Add model validation support for EdgeOne provider

Features

• No API key required - uses EdgeOne's built-in AI service
• OpenAI-compatible API interface
• Streaming response support with native tool calling
• Automatic deployment to EdgeOne Pages

Files

• edge-functions/api/edgeai/chat/completions.ts - Edge Function implementation
• edgeone.json - EdgeOne Pages configuration
• lib/ai-providers.ts - Provider registration
• components/model-selector.tsx - UI integration
• app/api/validate-model/route.ts - Model validation

[DayuanJiang]

Thanks for the contribution, merged.