[Bug] fix: Backend has no input validation on GDB command execution

[Lalit7374]

Description

The Flask backend accepts GDB commands from the frontend and executes them
without proper input validation or sanitization. This is both a security
concern and a reliability issue that can crash the server.

Problem

• No validation on incoming command input — empty/null strings crash the server
• No standardized JSON error response format — frontend cannot handle failures
• Missing proper HTTP status codes on error (returns 200 even on failures)
• No try/except around GDB command execution in the backend

Steps to Reproduce

1. Send an empty string or null as a GDB command via the API
2. Observe server crash or unhandled exception in terminal
3. Frontend receives no meaningful error to display

Proposed Solution

• Add input validation using Flask request parsing with checks for empty input
• Return proper HTTP status codes: 400 for bad input, 500 for server errors
• Wrap all GDB command execution in try/except blocks
• Return structured JSON error responses: {"error": "message", "status": 400}
• Add basic sanitization to reject null or empty command strings

I'd like to fix this

Will explore /gdbui_server/main.py and submit a focused PR.

[Gauravi004]

I would like to work on this issue