Add macOS native titlebar support

src/lib/components/TitleBar.svelte

@@ -7,6 +7,7 @@
 	} = $props();
 
 	const appWindow = getCurrentWindow();
+	const isMac = navigator.platform.startsWith('Mac');
 	let maximized = $state(false);
 
 	async function checkMaximized() {
@@ -59,7 +60,7 @@
 </script>
 
 <!-- svelte-ignore a11y_no_static_element_interactions -->
-<div class="titlebar" onmousedown={handleMouseDown}>
+<div class="titlebar" class:macos={isMac} onmousedown={handleMouseDown}>
 	<div class="titlebar-brand">
 		<svg width="18" height="18" viewBox="0 0 48 48" fill="none">
 			<rect width="48" height="48" rx="12" fill="var(--accent)" />
@@ -96,6 +97,7 @@
 			New Note
 		</button>
 	</div>
+	{#if !isMac}
 	<div class="titlebar-controls">
 		<button class="titlebar-btn" onclick={minimize} title="Minimize">
 			<svg width="10" height="10" viewBox="0 0 10 10">
@@ -121,6 +123,7 @@
 			</svg>
 		</button>
 	</div>
+	{/if}
 </div>
 
 <style>
@@ -252,4 +255,9 @@
 		background: #e81123;
 		color: white;
 	}
+
+	/* macOS: add left padding for native traffic light buttons */
+	.titlebar.macos .titlebar-brand {
+		padding-left: 78px;
+	}
 </style>