feat(sensing): native macOS CoreWLAN WiFi sensing adapter

Add native macOS LiDAR / WiFi sensing support via CoreWLAN:
- mac_wifi.swift: Swift helper to poll RSSI/Noise at 10Hz
- MacosWifiCollector: Python adapter for the sensing pipeline
- Auto-detect Darwin platform in ws_server.py

v1/src/sensing/mac_wifi.swift

@@ -0,0 +1,34 @@
+import Foundation
+import CoreWLAN
+
+// Output format: JSON lines for easy parsing by Python
+// {"timestamp": 1234567.89, "rssi": -50, "noise": -90, "tx_rate": 866.0}
+
+func main() {
+    guard let interface = CWWiFiClient.shared().interface() else {
+        fputs("{\"error\": \"No WiFi interface found\"}\n", stderr)
+        exit(1)
+    }
+
+    // Flush stdout automatically to prevent buffering issues with Python subprocess
+    setbuf(stdout, nil)
+
+    // Run at ~10Hz
+    let interval: TimeInterval = 0.1
+
+    while true {
+        let timestamp = Date().timeIntervalSince1970
+        let rssi = interface.rssiValue()
+        let noise = interface.noiseMeasurement()
+        let txRate = interface.transmitRate()
+
+        let json = """
+        {"timestamp": \(timestamp), "rssi": \(rssi), "noise": \(noise), "tx_rate": \(txRate)}
+        """
+        print(json)
+
+        Thread.sleep(forTimeInterval: interval)
+    }
+}
+
+main()