[FEATURE] Add job cancellation endpoint and frontend button for long-running scans

[adikulkarni006]

Problem
Scans can take several minutes (especially large repos). If a user starts a scan by mistake or it's taking too long, there's no way to cancel it. The UI just waits or the user has to refresh/close.

Expected behavior

• Backend: POST /jobs/{job_id}/cancel that sets a cancellation flag.
• The scanning process (SAST, dependency, secrets) should periodically check this flag and abort cleanly.
• Frontend: Add "Cancel Scan" button on the dashboard while scanning is in progress.
• After cancellation, job status becomes "cancelled".

Technical hints

• Use asyncio cancellation or a shared cancel_event dict.
• Modify scanner functions to accept a cancel_event and check it between major steps.
• Update frontend to poll job status and show cancel button when status is "running".

Labels: enhancement, good first issue, SSoC26

[shreyagupta2006]

hey @maintainer please this assign this issue to me under SSoc 2026

[adikulkarni006]

Assigned to you. Please follow the contributing guidelines. Create a branch, fix the issue, and submit a PR. Good luck!

[aditya-sharma-devs]

Hi @maintainer, I would like to work on this issue under SSOC'26, Kindly assign it to me .
Thank you.