feat: add edu & college vendor extension commands
Add five hidden vendor extension commands for education scenarios:
- edu-contact: school/class/family/teacher contact management
- edu-group: student/class group lifecycle
- edu-app: homework, notices, report cards, diplomas, class circles
- edu-familygroup: family group management, child binding, app permissions
- college-contact: university dept/employee/alumni/graduate management
All route to dedicated MCP servers via callMCPToolOnServer with endpoints
registered in openSupplementServers (helper-only, not VisibleProducts).
Includes: helper implementations, dispatch tests, mono/multi skill docs,
coverage.yaml registration, context-budget compliance, and .changes fragment.
听荷
f3e98d55e8