Remove udev rules, add GNOME desktop entry & SVG icon, and support V4L2-only open on Linux

assets/insta360-link-controller.desktop

@@ -0,0 +1,14 @@
+[Desktop Entry]
+Version=1.0
+Type=Application
+Name=Insta360 Link Controller
+GenericName=Webcam Controller
+Comment=Hardware PTZ, AI tracking, image settings, and live preview controller for Insta360 Link webcams
+Exec=insta360-link-gui
+TryExec=insta360-link-gui
+Icon=insta360-link-controller
+Terminal=false
+Categories=AudioVideo;Video;Settings;HardwareSettings;
+Keywords=insta360;link;webcam;camera;ptz;gimbal;uvc;video;tracking;
+StartupNotify=true
+StartupWMClass=insta360-link-controller

assets/insta360-link-controller.svg

@@ -0,0 +1,18 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 128 128" width="128" height="128">
+  <defs>
+    <linearGradient id="bg" x1="0" y1="0" x2="1" y2="1">
+      <stop offset="0%" stop-color="#181c24"/>
+      <stop offset="100%" stop-color="#0e1117"/>
+    </linearGradient>
+    <linearGradient id="ring" x1="0" y1="0" x2="1" y2="1">
+      <stop offset="0%" stop-color="#00e676"/>
+      <stop offset="100%" stop-color="#00b248"/>
+    </linearGradient>
+  </defs>
+  <rect x="8" y="8" width="112" height="112" rx="26" fill="url(#bg)" stroke="#2a3140" stroke-width="3"/>
+  <rect x="34" y="24" width="60" height="46" rx="14" fill="#232936" stroke="url(#ring)" stroke-width="4"/>
+  <circle cx="64" cy="47" r="14" fill="#0d1016" stroke="#00e676" stroke-width="3"/>
+  <circle cx="64" cy="47" r="6" fill="#00e676"/>
+  <path d="M52 70 L52 86 L76 86 L76 70" fill="#232936" stroke="#3a4254" stroke-width="3" stroke-linejoin="round"/>
+  <rect x="36" y="86" width="56" height="14" rx="7" fill="#2b3242" stroke="#00e676" stroke-width="2.5"/>
+</svg>