[RNE Rewrite] docs(skills): add clang-tidy and check-cpp-warnings to verify-and-build skill

[barhanc]

Description

Updates .agents/skills/verify-and-build/SKILL.md to document the project's C++ static analysis checks:

• lint:cpp (clang-tidy): Added steps to run static analysis using Homebrew LLVM.
• check-cpp-warnings.sh : Documented how to run the compiler warning check manually.

Introduces a breaking change?

• Yes
• No

Type of change

• Bug fix (change which fixes an issue)
• New feature (change which adds functionality)
• Documentation update (improves or adds clarity to existing documentation)
• Other (chores, tests, code style improvements etc.)

Tested on

• iOS
• Android

Testing instructions

N/A

Screenshots

Related issues

Checklist

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have updated the documentation accordingly
• My changes generate no new warnings

Additional notes