refactor: code cleanup and App.jsx component split

fix: resolve ModuleNotFoundError and simplify CI/CD

ci: skip backend-tests job on pull_request (heavy GPU deps)

fix(ci): bump Node.js to 22 for ESLint 10 compatibility

fix(ci): install backend/requirements.txt in CI workflow

feat: implement comprehensive CI/CD pipeline with mock AI mode

Update Docker CI workflow for BIAF build process

Update dependency review workflow configuration

Update CodeQL workflow for Python analysis

Update Pylint workflow configuration

Refactor Python CI workflow for better structure