Flatten repo structure: move crawler/ to root, remove vqa/ and immoweb/

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.

frontend/src/utils/mapUtils.ts

@@ -0,0 +1,45 @@
+// Map utility functions
+
+/**
+ * Deep clone an object using JSON serialization
+ */
+export function clone<T>(obj: T): T {
+  return JSON.parse(JSON.stringify(obj));
+}
+
+/**
+ * Calculate the value at a given percentile in a sorted array
+ * @param arr Sorted array of numbers
+ * @param p Percentile (0-1)
+ */
+export function percentile(arr: number[], p: number): number {
+  if (arr.length === 0) return 0;
+  if (typeof p !== 'number') throw new TypeError('p must be a number');
+  if (p <= 0) return arr[0];
+  if (p >= 1) return arr[arr.length - 1];
+
+  const index = arr.length * p;
+  const lower = Math.floor(index);
+  const upper = lower + 1;
+  const weight = index % 1;
+
+  if (upper >= arr.length) return arr[lower];
+  return arr[lower] * (1 - weight) + arr[upper] * weight;
+}
+
+/**
+ * Convert percentage-based color stops to value-based color stops
+ * @param colorStopsPerc Array of [percentage, color] tuples
+ * @param min Minimum value
+ * @param max Maximum value
+ */
+export function calculateColorStops(
+  colorStopsPerc: [number, string][],
+  min: number,
+  max: number
+): [number, string][] {
+  return colorStopsPerc.map(([perc, color]) => [
+    min + (perc * (max - min)) / 100,
+    color,
+  ]);
+}