feat(pos): Capacitor mobile app setup — Android + iOS wrapper

Set up Capacitor to wrap the Nexus POS web app as a native mobile app.
The app loads from the remote server URL so no bundling is needed.
Includes native-bridge.js for camera, push notifications, haptics,
and status bar integration when running inside the native shell.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

pos/capacitor.config.json

@@ -0,0 +1,17 @@
+{
+  "appId": "com.nexusautoparts.pos",
+  "appName": "Nexus POS",
+  "webDir": "www",
+  "server": {
+    "url": "https://nexus.consultoria-as.com/pos",
+    "cleartext": true
+  },
+  "plugins": {
+    "SplashScreen": {
+      "launchShowDuration": 2000,
+      "backgroundColor": "#0d0d0d",
+      "showSpinner": true,
+      "spinnerColor": "#F5A623"
+    }
+  }
+}