security: dependency audit and pin critical dependencies in CI

[ayushkrtiwari]

Task Description
Run pip-audit or safety in CI and pin versions of critical dependencies. Add a scheduled workflow to run dependency audit weekly.

Goal
Avoid introducing known-vulnerable versions via updates.

Suggestions

• Add job in .github/workflows/security.yml to run pip-audit
• Add requirements-dev.txt with pinned versions for CI, or use Poetry lock file

Labels: security, ci
Difficulty: easy

[saumya1317]

hii can you assign this to me?

[ayushkrtiwari]

@saumya1317 you have been assigned this issue