Initial commit -- Core Cooldown v0.1.0

Portable Windows break timer to prevent RSI and eye strain.
Tauri v2 + Svelte 5 + Tailwind CSS v4. No installer, no telemetry,
no data leaves the machine. CC0 public domain.

src/lib/components/ToggleSwitch.svelte

@@ -0,0 +1,32 @@
+<script lang="ts">
+  import { config } from "../stores/config";
+
+  interface Props {
+    checked: boolean;
+    onchange?: (value: boolean) => void;
+  }
+
+  let { checked = $bindable(), onchange }: Props = $props();
+
+  function toggle() {
+    checked = !checked;
+    onchange?.(checked);
+  }
+</script>
+
+<button
+  type="button"
+  role="switch"
+  aria-label="Toggle"
+  aria-checked={checked}
+  class="relative inline-flex h-[24px] w-[48px] shrink-0 cursor-pointer rounded-full
+         transition-colors duration-200 ease-in-out focus:outline-none"
+  style="background: {checked ? $config.accent_color : '#1a1a1a'};"
+  onclick={toggle}
+>
+  <span
+    class="pointer-events-none inline-block h-[19px] w-[19px] rounded-full
+           shadow-sm transition-transform duration-200 ease-in-out
+           {checked ? 'translate-x-[26px] bg-white' : 'translate-x-[3px] bg-[#444]'} mt-[2.5px]"
+  ></span>
+</button>