* security: add log injection attack prevention with input sanitization
- Created src/utils/log_sanitizer.py to sanitize user-controlled input before logging
- Prevents log injection attacks using newlines, tabs, carriage returns, etc.
- Escapes dangerous characters: \n, \r, \t, \0, \x1b
- Provides specialized functions for different input types:
- sanitize_log_input: general purpose sanitization
- sanitize_thread_id: for user-provided thread IDs
- sanitize_user_content: for user messages (more aggressive truncation)
- sanitize_agent_name: for agent identifiers
- sanitize_tool_name: for tool names
- sanitize_feedback: for user interrupt feedback
- create_safe_log_message: template-based safe message creation
- Updated src/server/app.py to sanitize all user input in logging:
- Thread IDs from request parameter
- Message content from user
- Agent names and node information
- Tool names and feedback
- Updated src/agents/tool_interceptor.py to sanitize:
- Tool names during execution
- User feedback during interrupt handling
- Tool input data
- Added 29 comprehensive unit tests covering:
- Classic newline injection attacks
- Carriage return injection
- Tab and null character injection
- HTML/ANSI escape sequence injection
- Combined multi-character attacks
- Truncation and length limits
Fixes potential log forgery vulnerability where malicious users could inject
fake log entries via unsanitized input containing control characters.
