Fix PyPI and npm release publishers

[adtyavrdhn]

The latest v0.1.5 release run reached both publish jobs, but each failed before uploading:

• the pinned pypa/gh-action-pypi-publish rejected the wheel's Metadata-Version 2.5
• npm parsed the unprefixed tarball path as a GitHub shorthand and attempted an SSH lookup

This restores the previously used uv trusted-publishing flow for PyPI and prefixes the npm tarball with ./ so npm treats it as a local package.

Validation:

• pre-commit (including YAML, Prettier, and zizmor)
• uv 0.12.1 publish --dry-run --trusted-publishing never against the exact failed v0.1.5 artifacts; uv discovered and accepted both dist/* files
• npm publish --dry-run ./npm-dist/pydantic-genai-prices-*.tgz --access public against the exact failed v0.1.5 artifact

[cubic-dev-ai]

No issues found across 1 file

_{Re-trigger cubic}