feat(security): add sanitized command preview before scan execution

[aaniya22]

Closes #35

Summary

Adds a live sanitized command preview panel to the scan configuration page, so users can see what SecuScan is about to run before submitting — with secrets always redacted.

Changes

• frontend/src/utils/commandPreview.ts — utility for redaction, sensitive field detection, and token building
• frontend/src/components/CommandPreview.tsx — live preview panel component
• frontend/src/api.ts — added sensitive? and command_template? fields to types
• frontend/src/pages/ToolConfig.tsx — wired in the preview panel
• frontend/testing/unit/utils/commandPreview.test.ts — 22 unit tests
• frontend/testing/unit/pages/ToolConfigDynamic.test.tsx — additional integration tests

Acceptance Criteria

• ✅ Users can preview the generated command before starting a scan
• ✅ Sensitive fields (tokens, passwords, cookies, auth headers, vault refs) are redacted
• ✅ Preview updates live when form inputs change
• ✅ Scan submission behaviour is unchanged — original inputs always sent
• ✅ Tests cover redaction and generated preview cases

[aaniya22]

please review and merge this pr
Also kindly add gssoc:approved label to the pr
thank you

[aaniya22]

please review and merge this pr
Also kindly add gssoc:approved label to the pr
thank you

[utksh1]

Blocking issues before merge:

• The PR adds an empty file at frontend/frontend/e2e/scan-workflow.spec.ts (note the duplicated frontend/ path). Please remove this file and ensure E2E specs live under frontend/e2e/.
• This PR mixes multiple concerns (command preview + reports changes + E2E). Please consider splitting into focused PRs to reduce review/merge conflicts.

Once the stray path is removed and scope is clarified, happy to re-review.