feat: Add VS Code launch/task configurations and refactor app icon and resource management.

app/KeychainHelper.swift

@@ -0,0 +1,37 @@
+import Foundation
+
+// Note: Switched to File-based storage to avoid repetitive System Keychain prompts
+// during development (Unsigned Binary). Files are set to 600 layout (User Only).
+class KeychainHelper {
+  static let shared = KeychainHelper()
+
+  private var storeURL: URL {
+    let home = FileManager.default.homeDirectoryForCurrentUser
+    return home.appendingPathComponent(".mole").appendingPathComponent(".key")
+  }
+
+  func save(_ data: String) {
+    let url = storeURL
+    do {
+      try FileManager.default.createDirectory(
+        at: url.deletingLastPathComponent(), withIntermediateDirectories: true)
+      try data.write(to: url, atomically: true, encoding: .utf8)
+      // Set permissions to User Read/Write Only (600) for security
+      try FileManager.default.setAttributes([.posixPermissions: 0o600], ofItemAtPath: url.path)
+    } catch {
+      print("Failed to save credentials: \(error)")
+    }
+  }
+
+  func load() -> String? {
+    do {
+      return try String(contentsOf: storeURL, encoding: .utf8)
+    } catch {
+      return nil
+    }
+  }
+
+  func delete() {
+    try? FileManager.default.removeItem(at: storeURL)
+  }
+}