feat!: replace mypy with ty

[lsorber]

Changes:

• Replace mypy with ty
• Add the ty VS Code extension
• Disable the Python language server (as recommended by ty)

[Copilot]

Pull request overview

This PR replaces the mypy type checker with ty (a new type checker from Astral) and updates all related configurations and documentation accordingly.

Key changes:

• Replaced mypy dependency with ty (>=0.0.5)
• Updated pre-commit hooks to use ty check instead of mypy
• Configured ty with appropriate settings for type checking, including strict mode support
• Updated VS Code development environment to use the ty extension and disable the Python language server

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
template/pyproject.toml.jinja	Removed mypy dependency and configuration; added ty dependency (>=0.0.5) and configuration sections for environment, rules, and terminal settings
template/.pre-commit-config.yaml.jinja	Updated pre-commit hook from mypy to ty check, added require_serial flag, and changed file types to include .pyi stub files
template/.devcontainer/devcontainer.json.jinja	Added astral-sh.ty VS Code extension, removed ms-python.mypy-type-checker extension, removed mypy-specific settings, disabled Python language server, and removed ruff.logLevel setting
README.md	Updated documentation to reference ty instead of mypy, standardized tool names to lowercase, and updated Dependabot documentation URL

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.