feat(ui): add InputColor and custom theme

packages/ui/src/routes/Theme.svelte

@@ -0,0 +1,80 @@
+<script lang="ts">
+  import { InputColor } from '$lib';
+
+  interface Props {
+    theme?: string;
+  }
+
+  let { theme }: Props = $props();
+
+  const colors = [
+    'layer-0',
+    'layer-1',
+    'layer-2',
+    'layer-3',
+    'active',
+    'selected',
+    'outline',
+    'connection',
+    'text'
+  ];
+
+  let customColors = $state<CustomColors>({
+    text: [205, 214, 244],
+    outline: [62, 62, 79],
+    'layer-0': [6, 6, 27],
+    'layer-1': [23, 23, 46],
+    'layer-2': [49, 50, 68],
+    'layer-3': [168, 170, 200],
+    active: [0, 0, 0],
+    selected: [38, 139, 210],
+    connection: [131, 148, 150]
+  });
+
+  const themeCss = $derived.by(() => {
+    return `<style>html.theme-custom{
+  ${
+      Object.keys(customColors)
+        .map((v) => {
+          return `--color-${v}: rgb(${customColors[v].join(',')});`;
+        })
+        .join('\n')
+    }
+</style>`;
+  });
+</script>
+
+<svelte:head>
+  {@html themeCss}
+</svelte:head>
+
+<table>
+  <thead>
+    <tr>
+      <th>Color</th>
+      <th>Name</th>
+      <th>Custom</th>
+    </tr>
+  </thead>
+  <tbody>
+    {#each colors as color (color)}
+      <tr>
+        <td>
+          <div class="w-6 h-6 mr-2 my-1 rounded-sm outline-1 bg-{color}"></div>
+        </td>
+        <td>{color}</td>
+        <td>
+          <InputColor bind:value={customColors[color]} />
+        </td>
+      </tr>
+    {/each}
+  </tbody>
+</table>
+
+<style>
+  table {
+    border-spacing: 5px;
+    border-collapse: separate;
+    text-align: left;
+    margin-left: 5px;
+  }