fix(ci): pin setup-uv and ignore stray root file

[buddingengineers12345]

What

• Fixes GitHub Actions workflows by pinning astral-sh/setup-uv to a concrete release tag.
• Deletes the stray root file 1 and adds /1 to .gitignore so it won’t be re-committed.
• Removes any use of override in scripts/bump_version.py and disables reportImplicitOverride in BasedPyright config for this repo.
• Renames the template package helper module directory from template/src/{{ package_name }}/_support to template/src/{{ package_name }}/common, updating internal imports and coverage omit patterns.

Why

• The repo’s workflows referenced an unstable/non-existent setup-uv tag, which breaks CI.
• The 1 file appears accidental and should not live in the repo.
• CI type checking was failing due to override import/decorator expectations.
• common is a clearer, less “private/internal” name than _support for generated projects.

Verification

• just ci
• uv run basedpyright