Feature: uv and ruff

[rosemcc]

This pull request migrates the project from Poetry and Poethepoet to using uv for Python dependency management and ruff for formatting and linting. It updates the dependency and development workflow, modernizes the configuration files, and makes related documentation and script changes.

Dependency and build system migration:

• Replaces Poetry with uv for dependency management, updating pyproject.toml to use PEP 621 metadata, hatchling as the build backend, and new dependency group syntax. Removes Poethepoet tasks and adds ruff configuration.
• Updates the GitHub Actions workflow to use uv and ruff for dependency installation and code checks, replacing all Poetry usage. [1] [2]
• Updates shell scripts (check_activescale.sh) to require and use uv instead of Poetry. [1] [2]

Documentation updates:

• Updates README.md and src/api/README.md to document the new uv and ruff-based workflow, replacing all instructions referencing Poetry or Poethepoet. [1] [2] [3]
• Updates TODO.md to mark the migration as complete and reflect the new setup steps.

Code improvements and cleanup:

• Refactors error message formatting in API routers for clarity and consistency, combining multi-line strings into single f-strings. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12]
• Minor API type hint and code style improvements for FastAPI endpoints. [1] [2]
• Modernizes imports and enum usage in src/models/common.py.