Fix CampusNAS recovery after VPN loss

Sources/CampusNASMonitor/Probe.swift

@@ -15,6 +15,19 @@ private final class ResumeOnce: @unchecked Sendable {
     }
 }
 
+/// `Process.terminate()` only sends SIGTERM. A wedged network client (notably
+/// `smbutil` after a tunnel disappears) may ignore it and keep the pipe open,
+/// leaving the reader thread in `readDataToEndOfFile()` forever. Escalate to
+/// SIGKILL after a short grace period so every probe is actually bounded.
+private func stop(_ process: Process) {
+    guard process.isRunning else { return }
+    process.terminate()
+    let pid = process.processIdentifier
+    DispatchQueue.global().asyncAfter(deadline: .now() + 1) {
+        if process.isRunning { Darwin.kill(pid, SIGKILL) }
+    }
+}
+
 enum Probe {
     /// Runs a command and reports whether it exited 0. A process that outlives
     /// `timeout` is killed and treated as failure — the VPN wrapper can block on
@@ -51,7 +64,7 @@ enum Probe {
 
             DispatchQueue.global().asyncAfter(deadline: .now() + timeout) {
                 guard process.isRunning else { return }
-                process.terminate()
+                stop(process)
                 if once.claim() { continuation.resume(returning: false) }
             }
         }
@@ -119,7 +132,7 @@ enum Probe {
 
             DispatchQueue.global().asyncAfter(deadline: .now() + timeout) {
                 guard process.isRunning else { return }
-                process.terminate()
+                stop(process)
                 if once.claim() {
                     continuation.resume(returning: RunResult(
                         ok: false, output: "", error: "timeout after \(timeout)s"))
@@ -170,7 +183,7 @@ enum Probe {
 
             DispatchQueue.global().asyncAfter(deadline: .now() + timeout) {
                 guard process.isRunning else { return }
-                process.terminate()
+                stop(process)
                 if once.claim() { continuation.resume(returning: nil) }
             }
         }