fix: add explicit macOS sandbox entitlements — client only, no server

Apple rejected v1.5.9 for com.apple.security.network.server entitlement
(Guideline 2.4.5(i)). NostrKey only makes outgoing WebSocket connections,
not incoming. Explicitly set app-sandbox + network.client on both macOS
targets to prevent Xcode from auto-adding network.server.

Author: vveerrgg

dev/apple/macOS (App)/nostrkey.entitlements

@@ -1,5 +1,10 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
-<dict/>
+<dict>
+	<key>com.apple.security.app-sandbox</key>
+	<true/>
+	<key>com.apple.security.network.client</key>
+	<true/>
+</dict>
 </plist>

dev/apple/macOS (Extension)/nostrkey.entitlements

@@ -1,5 +1,10 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
-<dict/>
+<dict>
+	<key>com.apple.security.app-sandbox</key>
+	<true/>
+	<key>com.apple.security.network.client</key>
+	<true/>
+</dict>
 </plist>