Fix categories

hdyc-svelte/src/lib/data/calculators.ts

@@ -39,6 +39,29 @@ export const categories: Record<string, { label: string; icon: string }> = {
   other:           { label: 'Other',               icon: '🔄' },
 };
 
+export const categoryOrder = [
+  'length',
+  'weight',
+  'temperature',
+  'volume',
+  'fluids',
+  'area',
+  'speed',
+  'pressure',
+  'energy',
+  'magnetism',
+  'power',
+  'data',
+  'time',
+  'angle',
+  'number-systems',
+  'radiation',
+  'electrical',
+  'force',
+  'light',
+  'other',
+] as const;
+
 export const calculators: CalculatorDef[] = [
   {"slug": "inches-to-feet", "name": "Inches to Feet", "category": "length", "type": "standard", "teaser": "If a shelf spans 36 inches, how many feet of trim does it cover?", "labels": {"in1": "Inches", "in2": "Feet"}, "factor": 12.0},
   {"slug": "kilograms-to-pounds", "name": "Kilograms to Pounds", "category": "weight", "type": "standard", "labels": {"in1": "Kilograms", "in2": "Pounds"}, "factor": 2.20462262},
@@ -1319,11 +1342,14 @@ export function getCalculatorsByCategory(category: string): CalculatorDef[] {
 }
 
 export function getCategoriesWithCounts(): { key: string; label: string; icon: string; count: number }[] {
-  return Object.entries(categories).map(([key, meta]) => ({
-    key,
-    ...meta,
-    count: calculators.filter(c => c.category === key && !c.hidden).length,
-  }));
+  return categoryOrder
+    .map(key => {
+      const meta = categories[key];
+      if (!meta) return null;
+      const count = calculators.filter(c => c.category === key && !c.hidden).length;
+      return { key, ...meta, count };
+    })
+    .filter(Boolean) as { key: string; label: string; icon: string; count: number }[];
 }
 
 export function searchCalculators(query: string): CalculatorDef[] {