feat: Add Filter, ListViewSwitcher, SearchBar, and ThemeSwitcher components

- Implemented Filter component for managing tags and brands with localStorage and URL parameter updates.
- Created ListViewSwitcher component to toggle between compact, grid, and list views.
- Developed SearchBar component with global hotkey support for quick access and URL search parameter management.
- Added ThemeSwitcher component to allow users to switch between system, light, and dark themes.

src/components/ThemeSwitcher.svelte

@@ -0,0 +1,84 @@
+<script>
+  export let theme = "system";
+  export let setTheme = () => {};
+</script>
+
+<div class="theme-switcher">
+  <div class="theme-switch-group button-group">
+    <button
+      on:click={() => setTheme("system")}
+      class:active={theme === "system"}
+      aria-label="System theme"
+    >
+      <svg
+        width="20"
+        height="20"
+        viewBox="0 0 20 20"
+        fill="none"
+        xmlns="http://www.w3.org/2000/svg"
+        ><circle
+          cx="10"
+          cy="10"
+          r="8"
+          stroke="currentColor"
+          stroke-width="2"
+        /><path
+          d="M10 2a8 8 0 0 1 8 8"
+          stroke="currentColor"
+          stroke-width="2"
+        /></svg
+      >
+    </button>
+    <button
+      on:click={() => setTheme("light")}
+      class:active={theme === "light"}
+      aria-label="Light mode"
+    >
+      <svg
+        width="20"
+        height="20"
+        viewBox="0 0 20 20"
+        fill="none"
+        xmlns="http://www.w3.org/2000/svg"
+        ><circle
+          cx="10"
+          cy="10"
+          r="5"
+          stroke="currentColor"
+          stroke-width="2"
+        /><path
+          d="M10 1v2M10 17v2M3.22 3.22l1.42 1.42M15.36 15.36l1.42 1.42M1 10h2M17 10h2M3.22 16.78l1.42-1.42M15.36 4.64l1.42-1.42"
+          stroke="currentColor"
+          stroke-width="2"
+        /></svg
+      >
+    </button>
+    <button
+      on:click={() => setTheme("dark")}
+      class:active={theme === "dark"}
+      aria-label="Dark mode"
+    >
+      <svg
+        width="20"
+        height="20"
+        viewBox="0 0 20 20"
+        fill="none"
+        xmlns="http://www.w3.org/2000/svg"
+        ><path
+          d="M15.5 13A7 7 0 0 1 7 4.5a7 7 0 1 0 8.5 8.5z"
+          stroke="currentColor"
+          stroke-width="2"
+        /></svg
+      >
+    </button>
+  </div>
+</div>
+
+<style>
+  .theme-switcher {
+    display: flex;
+    align-items: center;
+    gap: 0.2rem;
+    margin-left: auto;
+  }
+</style>