Simplify the filter UI to show only essential filters (type toggle, price/bedroom
range sliders, min size) by default, with advanced filters collapsed. Extract
visualization controls (color-by metric, POI travel mode) into a separate
VisualizationCard component. Wire up previously ignored backend filters: max_sqm,
min/max_price_per_sqm, and district_names now work end-to-end.
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.