Fix system sleep prevention and add comprehensive test suite

- Fixed terminal control preventing system sleep by improving rustyline configuration and adding proper cleanup
- Added signal handling for graceful termination and terminal state reset
- Implemented comprehensive test suite with 58 unit and integration tests
- Added testing dependencies: tempfile, mockall, tokio-test, serial_test
- Created proper Drop implementation for InputHandler to ensure terminal cleanup
- Enhanced exit handling in both normal exit and /exit command

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

test_export.md

@@ -0,0 +1,19 @@
+# Conversation: integration_test
+
+**Model:** gpt-4o
+**Web Search:** Enabled
+**Reasoning Summary:** Disabled
+**Reasoning Effort:** medium
+**Extended Thinking:** Disabled
+**Thinking Budget:** 5000 tokens
+
+---
+
+## 👤 User
+
+Hello, test message
+
+## 🤖 Assistant
+
+Hello! This is a test response.
+