docs: improve adoption guide with ci examples, add benchmark
- fix import path example (your_project.models not src.models.models)
- add pre-commit, justfile, and github actions examples
- add bench.py for measuring performance on real lexicons
- add `just bench` target
benchmark results (297 atproto lexicons → 2669 lines):
cold generation: ~0.17s
cache hit: ~0.07s
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>