agent-skill-groups v0.3.50

Adds Codex agents/openai.yaml metadata auditing to the budget command.\n\n- Parses interface.display_name, interface.short_description, interface.default_prompt, and dependencies.tools.\n- Reports per-skill Codex interface/tool metadata and summary counts in budget --json.\n- Keeps policy.allow_implicit_invocation handling for explicit-only skills.\n- Updates docs and install pages for v0.3.50.\n\nVerified locally with pytest, self-test, build, fresh wheel install, and GitHub CI/Pages.