Initial commit: KPopBird - macOS sleep prevention menu bar app

Swift macOS menu bar app with Samjokoo (삼족오) icon.
Features: display/system sleep prevention, timer mode, battery awareness, auto-start on login.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Package.swift

@@ -0,0 +1,13 @@
+// swift-tools-version:5.9
+import PackageDescription
+
+let package = Package(
+    name: "KPopBird",
+    platforms: [.macOS(.v13)],
+    targets: [
+        .executableTarget(
+            name: "KPopBird",
+            path: "Sources/KPopBird"
+        )
+    ]
+)