Add new cybersecurity skills for injection and config reviews

[VictorRayIO]

Hi there,
I've put together some new cybersecurity skills focusing on injection flaws and configuration reviews. These are fully aligned with the required SKILL.md format and include practical test payloads.
Let me know if any adjustments are needed. Cheers!

[mukul975]

Thanks for the 7 web-vuln review skills (cmd-injection, CORS, CSRF, insecure-file-uploads, JWT, LFI, open-redirect) — good coverage and a useful detection/review angle distinct from the existing exploitation skills. A few fixes before merge:

1. Placeholder code in all 7 files. Each skill has an echo test 'Verification block' / 'Initialize and execute' placeholder. Replace these with real, runnable verification steps (no placeholders, per repo standard).
2. Orphaned step stubs. cmd-injection and open-redirect have a leftover ## Standard Execution Steps / '2. Execute the sequence.' stub — please remove or complete.
3. Folder placement. Move each skill to skills/<skill-name>/ matching the standard layout (SKILL.md + references/ + scripts/agent.py + LICENSE).
4. name vs H1. Reconcile the frontmatter name: with the H1 title in each file.
5. ATT&CK mappings. Review the weaker ones (CSRF/CORS → T1189, open-redirect → T1566 are loose) and tighten to the most specific applicable technique.

Once the placeholders are gone and the layout matches, this is close.