fix: remove unused settings_read/settings_write permissions from plugin.json

Only process permission is required for tailscale + clipboard commands.
Least-privilege fix. Fixes #16

tailscalectl/plugin.json

@@ -7,5 +7,5 @@
   "icon": "vpn_key",
   "type": "widget",
   "component": "./TailscaleWidget.qml",
-  "permissions": ["settings_read", "settings_write", "process"]
+  "permissions": ["process"]
 }