feat(usecases): add skill property files for en/ru locales

Update: CONTRIBUTING.md

Add Humanizer skill

chore(release): 0.2.0

refactor(skills): merge usecase-map-puml into usecases with progressive disclosure

feat(humanizer): add author field to skill property files

fix(humanizer): unify Humanizer label capitalization in property files

feat(humanizer): add skill property files for en/ru locales

feat: split skill into en and ru versions

Merge pull request #300 from blader/changelog-readme

Describe this release's README changes in the changelog

Merge pull request #299 from blader/readme-examples

Rebuild the README examples so the rewrite keeps the draft's substance

chore(openspec): archive plain-provider-links change

docs(openspec): sync plain provider links specs

fix(diagram): provider links as solid lines instead of duplicate circle

docs(openspec): propose plain provider links change

chore(release): 0.4.1

chore(openspec): archive system-required change

docs(openspec): sync system required specs

docs: system.required readme changelog and backlog closure

feat(generator): system.required rendering on context diagram and markdown

feat(schema): system.required field with semantic target rule