Add injection and server-side flaws detection skill

[VictorRayIO]

Hi,
I've put together a batch of new cybersecurity skills focusing on server-side vulnerabilities, specifically SQL injection, XXE, SSTI, and SSRF. 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 (insecure-configs, race-conditions, SQLi, SSRF, SSTI, XSS, XXE) — this complements #89 well and the review/detection framing is a good fit. Same fixes needed as #89 (same template):

1. Placeholder code in all 7 files. Remove the echo test 'Verification block' / 'Initialize and execute' placeholder and replace with real runnable steps.
2. Orphaned step stubs. insecure-configs and xxe-injection-risks have a leftover ## Standard Execution Steps / '2. Execute the sequence.' stub — remove or complete.
3. Folder placement. Move each to skills/<skill-name>/ with the standard layout (SKILL.md + references/ + scripts/agent.py + LICENSE).
4. name vs H1. Reconcile frontmatter name: with the H1 in each file.
5. ATT&CK mappings. Tighten the weaker mappings to the most specific applicable technique.

Solid content — just needs the placeholders cleaned and the layout aligned.

[VictorRayIO]

thank for approval, my latest request for review was an accident action , pls ignore it.