Introduces PointOfInterest (per-user named locations with lat/lng) and
POIDistance (travel time/distance per listing+POI+mode triple) SQLModel
entities, plus an Alembic migration to create both tables with indexes
and a composite unique constraint.
The crawler subdirectory was the only active project. Moving it to the
repo root simplifies paths and removes the unnecessary nesting. The
vqa/ and immoweb/ directories were legacy/unused and have been removed.
Updated .drone.yml, .gitignore, .claude/ docs, and skills to reflect
the new flat structure.