feat: optimize Docker build with multi-stage and expand documentation

- Implement multi-stage build using rust:1.98-slim and debian:bookworm-slim
- Install pkg-config and libfontconfig1-dev build dependencies for yeslogic-fontconfig-sys
- Install runtime dependencies libfontconfig1 and ca-certificates
- Reduce final container image size from ~1.1GB to ~100MB
- Expand README with quickstart, CLI options table, usage examples, and badges
- Add .gitignore for generated PDF files

refactor: [UPD] Dockerfile to use Rust and improve build process; [AD…

…D] MIT License

Merge pull request #1 from kelsoncm/snyk-fix-a4a188afdd5272908592c480…

…f3fd1822

[Snyk] Security upgrade ruby from 2.7.7 to 3.2.1-slim

first commit