* feat: mental model refresh history tracking and UI diff view
- DB migration: add history JSONB column to mental_models table
- Track previous content on each refresh in update_mental_model
- Add get_mental_model_history() engine method
- New GET /mental-models/{id}/history endpoint
- Control plane proxy route and getMentalModelHistory() in api.ts
- MentalModelDetailModal: add History tab with lazy loading, carousel
navigation (left=older, right=newer), word-level content diff view
* fix: resolve alembic migration head conflict for mental model history
* feat: mental model history tracking, side-by-side diff UI, and config flag
- Track content changes on every mental model update/refresh (persisted in JSONB history column)
- New GET /mental-models/{id}/history endpoint returning changes most-recent-first
- Side-by-side diff view in History tab (Before/After columns, line-level highlights)
- Actions dropdown in detail panel (Edit, Refresh, View History, Delete)
- HINDSIGHT_API_ENABLE_MENTAL_MODEL_HISTORY config flag (default: true)
- Also adds missing HINDSIGHT_API_ENABLE_OBSERVATION_HISTORY to configuration docs
- Python client wrapper method get_mental_model_history()
- Tests for history persistence (recorded, ordered, name-only skipped, missing returns None)
- Fix NameError: timezone not imported in update_mental_model
* fix: call get_mental_model_history before delete in doc example
e2baca8bfe