Normalize sidebar units and record registry updates

hdyc-svelte/src/lib/components/Sidebar.svelte

@@ -12,26 +12,35 @@
     conversions: CalculatorDef[];
   };
 
+  type UnitBucket = {
+    label: string;
+    conversions: CalculatorDef[];
+  };
+
   $: categoryUnitGroups = Object.entries(categories).map(([key, meta]) => {
-    const buckets = new Map<string, CalculatorDef[]>();
+    const buckets = new Map<string, UnitBucket>();
     const calcs = getCalculatorsByCategory(key);
 
     calcs.forEach(calc => {
       [calc.labels.in1, calc.labels.in2].forEach(unit => {
-        const existing = buckets.get(unit);
+        const key = unit.toLowerCase();
+        const existing = buckets.get(key);
         if (existing) {
-          existing.push(calc);
+          existing.conversions.push(calc);
         } else {
-          buckets.set(unit, [calc]);
+          buckets.set(key, {
+            label: unit,
+            conversions: [calc],
+          });
         }
       });
     });
 
     const units = [...buckets.entries()]
       .sort(([a], [b]) => a.localeCompare(b))
-      .map(([label, conversions]) => ({
-        label,
-        conversions: conversions.slice().sort((a, b) => a.name.localeCompare(b.name)),
+      .map(([, bucket]) => ({
+        label: bucket.label,
+        conversions: bucket.conversions.slice().sort((a, b) => a.name.localeCompare(b.name)),
       }));
 
     return { key, meta, units };