v0.1.2

docs: full README, AGENTS.md, Makefile, generated docs; bump 0.1.2

Bring lexware up to the family standard (was a 7-line README stub):
- README: full agent-ready README with badges, embedded CLI 'command
  surface' (--help), Why/Quick-start/Output-contract, family table
- add AGENTS.md (machine contract, incl. exit 8 = rate-limited and the
  429-as-HTTP-500 / 504-may-have-succeeded gotchas)
- add Makefile (help/install/test/test-unit/lint/docs/clean) and
  scripts/gen_docs.py; generate docs/COMMANDS.md (22 groups, 69 commands)
- pyproject: add Issues + Changelog URLs
Part of the cross-repo agent-tool CLI doc standardization.