Add automatic since table logic for incremental updates

- Added automatic since table management functions
- Enhanced CLI with automatic since detection and --force-full option
- Maintains sync timestamps for efficient incremental fetches
- Added comprehensive test suite maintaining 100% coverage
- Follows established patterns from pocket-to-sqlite

Closes #14

fix: update Sigstore action to v3.0.0 to resolve deprecated artifact …

…actions

- Update sigstore/gh-action-sigstore-python to v3.0.0
- Add retention-days to artifact upload for clarity
- Fixes deprecated artifact actions error in release workflow

fix: improve branch detection logic in publish workflow

- Use git merge-base instead of git branch for better CI compatibility
- Fetch main branch explicitly for accurate ancestor checking
- Fixes PyPI publishing branch detection issue

Merge pull request #57 from ryancheley/issue-46-upgrade-to-v9

🚀 Major modernization: API v9, modern tooling, and automated publishing

fix: apply ruff formatting and update workflow

Merge pull request #41 from ryancheley/pre-commit-ci-update-config

chore: [pre-commit.ci] pre-commit autoupdate

Merge pull request #41 from ryancheley/pre-commit-ci-update-config

chore: [pre-commit.ci] pre-commit autoupdate

Merge pull request #41 from ryancheley/pre-commit-ci-update-config

chore: [pre-commit.ci] pre-commit autoupdate

👷 more ci fixes

Merge pull request #18 from ryancheley/v0.6.0

V0.6.0