Properly parse number cells as floats

packages/frontend-core/src/components/grid/cells/NumberCell.svelte

@@ -2,6 +2,13 @@
   import TextCell from "./TextCell.svelte"
 
   export let api
+  export let onChange
+
+  const numberOnChange = value => {
+    const float = parseFloat(value)
+    const newValue = isNaN(float) ? null : float
+    onChange(newValue)
+  }
 </script>
 
-<TextCell {...$$props} bind:api type="number" />
+<TextCell {...$$props} onChange={numberOnChange} bind:api type="number" />