🎉 Echo v1.2.0 Release

This release brings three major improvements to enhance user experience and reliability.

✨ Features

1. 🌏 Complete Chinese Language Support

• Added full Chinese interface translation
• All components now support both English and Chinese
• Language selection in settings (disabled during exams)
• Localized content across all UI elements

2. 📨 Separated UI and Model Messages in File Converter

• Fixed language mixing issues when using Chinese interface
• System messages now display in user's selected language
• Model messages shown in separate "File Converter Message" box
• Applied to both success and error conversion scenarios
• Updated prompt examples to avoid exact question counts

3. ⏱️ Timeout Mechanism for Results Polling

• Added 60-second timeout to prevent indefinite waiting
• Failed questions display with 0 scores and timeout explanations
• Clear timeout warnings and user-friendly error messages
• Race condition protection for reliable operation
• Partial results always available even if some questions fail

🔧 Improvements

• Enhanced error handling across all question types
• Better visual distinction between different message types
• Improved file converter UX with separated message boxes
• More robust result processing with timeout protection

🐛 Bug Fixes

• Fixed language mixing in file converter (e.g., "成功! Extracted 4 questions")
• Prevent indefinite polling when questions fail to process
• Fix race conditions in timeout handling
• Ensure all questions appear in results even if processing fails

📊 Stats

• 16 files changed
• 1,008 additions, 137 deletions
• Major updates to frontend components and translation system