feat(skills): add NestJS security testing module

[ms6rb]

Summary

• Adds a NestJS security testing skill (strix/skills/frameworks/nestjs.md)
• Covers guard bypass, validation pipe exploits, module boundary leaks, cross-transport auth, JWT/Passport misuse, serialization leaks, ORM injection, and rate limiting bypass
• Includes practical testing methodology and validation requirements

Test plan

• Verify skill loads correctly via get_available_skills()
• Verify YAML frontmatter is parsed (name + description)
• Test against a NestJS target to validate coverage

[greptile-apps]

Greptile Summary

This PR adds a new NestJS security testing skill (strix/skills/frameworks/nestjs.md) that fits cleanly into the existing strix/skills/frameworks/ category alongside fastapi.md and nextjs.md. The file follows the required YAML frontmatter format (name + description), will be correctly discovered by get_available_skills() via the file stem, and its frontmatter will be stripped by _FRONTMATTER_PATTERN when loaded into agent context.

The content is comprehensive and well-organized, covering NestJS-specific attack surfaces (decorator pipeline, module system, multi-transport auth, ORM layer) with practical testing methodology matching the depth and structure of existing skills.

Issues found:

• The "Bypass Techniques" section contains a technically inaccurate claim that a permissive guard placed after a restrictive one can override its decision. NestJS guard chains use AND logic (all guards must return true); the actual bypass is metadata-driven (@Public() / Reflector) — which is already correctly described earlier in the skill.
• The "Validation Requirements" section is incomplete: it lacks explicit evidence criteria for ORM injection and cache poisoning findings, both of which have dedicated vulnerability sub-sections. Other framework skills (fastapi.md) map every major vulnerability class to a validation requirement.

Confidence Score: 4/5

• Safe to merge after correcting the technically inaccurate guard-ordering bypass claim; no functional code is changed.
• This is a documentation/skill file with no functional code changes. The file is structurally correct and will load without issues. The main concern is a misleading statement in "Bypass Techniques" that could cause an agent to misunderstand NestJS guard evaluation semantics and miss real bypass vectors, plus some gaps in validation requirements.
• strix/skills/frameworks/nestjs.md — review the guard-ordering bypass technique and expand validation requirements.

Important Files Changed

Filename	Overview
strix/skills/frameworks/nestjs.md	New NestJS security testing skill; well-structured and consistent with existing framework skills. One technically inaccurate bypass technique (guard ordering) and missing validation requirements for ORM injection and cache poisoning.

_{Last reviewed commit: a897bc4}