Add CampusNAS menu bar agent

Native macOS agent that keeps the office VPN and the NAS shares working
without the shell wrapper it replaces.

- VPN: full port of the `ovpn` script — host-route pinning, gateway
  discovery via networksetup, tunnel liveness by address plus pushed
  route, startup grace, restart of a wedged daemon. Root steps are
  batched into one system authorization prompt.
- SMB: mounts via NetFS, discovers shares from the server, detects
  mounts event-driven through NSWorkspace, matches the host by resolved
  alias so externally created mounts are recognised.
- Credentials never pass through the process: the VPN auth file is
  written by `security` straight to disk, and the password is stored via
  SecItemAdd rather than a command line visible in ps.
- UI: status window, settings editor, ⌘+/⌘− zoom that re-lays out rather
  than scaling a bitmap.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Package.swift

@@ -0,0 +1,14 @@
+// swift-tools-version:6.0
+import PackageDescription
+
+let package = Package(
+    name: "CampusNASMonitor",
+    platforms: [.macOS(.v13)],
+    targets: [
+        .executableTarget(
+            name: "CampusNASMonitor",
+            path: "Sources/CampusNASMonitor",
+            swiftSettings: [.swiftLanguageMode(.v5)]
+        )
+    ]
+)