What's New in v0.6.0

Higher-Order Constructs (HOC) — support for repeated-indicator and two-stage HOC modeling, automatic HOC detection, model expansion utilities, schema definitions and validation.

Measurement Invariance (MICOM) — full MICOM workflow for assessing measurement invariance across groups, with invariance assessment outputs and reporting structures.

Multi-Group Analysis (MGA) — MGA engine for comparing structural paths across groups, group comparison endpoints, result schemas, and significance testing of path differences.

Backend — new app/engine_mga.py; added /hoc and /mga API endpoints; extended parser and schema support for HOC, MICOM, and MGA workflows.

Frontend — major update to static/index.html with UI support for HOC and multi-group analysis workflows; improved results presentation.