Commit .env.development/.staging/.production and track env files in git
(matching uirefbase convention). No secrets: only NEXT_PUBLIC_BASE_PATH
and NEXT_PUBLIC_SHARED_API_PATH (basis backend). .gitignore now ignores
only *.local overrides.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
