ci: adopt centralized actions from github-actions repo

[tankdonut]

Summary

Replace inline workflow steps with centralized composite actions and reusable workflows from tankdonut/github-actions.

Changes

• lint-and-test.yaml: Replace inline asdf cache + install + pre-commit steps with tankdonut/github-actions/actions/pre-commit@v1. Keeps uv sync and pre-commit cache steps.
• build-and-publish-image.yaml: Replace inline podman login with tankdonut/github-actions/actions/ghcr-login@v1.
• prune-ghcr-images.yaml: Replace inline cleanup job with reusable workflow call to tankdonut/github-actions/.github/workflows/prune-ghcr.yaml@v1.
• bump-tool-versions.yaml: Replace inline git config with tankdonut/github-actions/actions/git-bot-config@v1.
• release.yaml: Replace inline git config with tankdonut/github-actions/actions/git-bot-config@v1 and inline crane auth login with tankdonut/github-actions/actions/ghcr-login@v1 (runtime: crane).

Verification

• All 5 YAML files parse as valid YAML.
• No inline git config --global commands remain.
• No inline podman login or crane auth login commands remain.
• All 6 centralized action references confirmed present.