MySkills v0.4.0

v0.4.0 — agent can manage AND grow the skill library (MCP)

- align: fix drifted/broken copies back to the canonical source (+ rollback)
- acquire: discover_search the skills.sh catalog + discover_install
- taxonomy: scenarios_create + skills_set_enabled (enable/disable per platform)
- the MCP now covers the full lifecycle: understand / organize / acquire /
  maintain / fix / clean — all gated + undoable