style: apply formatting and structural fixes

[nearlyforget]

Description:
This PR applies the stylistic and formatting corrections flagged by the new pre-commit configuration. It serves as
a "clean-up" pass to align the existing codebase with up coming pre commit hooks and CI check.

Key Changes:

• generate_models.sh: Fixed a shellcheck warning by adding || exit to the cd command, ensuring the script fails
  safely if the directory is missing.
• Package Init Files: Fixed missing end-of-file newlines in init.py files across the ucp_sdk models and
  schemas.
• Documentation & Workflows: Standardized formatting in README.md and .github/workflows/release.yml.
• Hygiene: Unified file endings and removed trailing whitespace across the repository.