Add Steam Input support for Big Picture Mode

Introduces a Steam Input bridge using steamworks.js, enabling native controller support in Big Picture Mode and on Steam Deck. Adds a new steam-input-manager.js module, integrates IPC handlers in main.js, exposes a steamInputAPI in preload.js, and updates bigpicture.js to use Steam Input when available with fallback to legacy Gamepad API. Updates dependencies and scripts in package.json for Steam Deck and Big Picture profiles.

package.json

@@ -5,22 +5,26 @@
   "main": "main.js",
   "scripts": {
     "start": "electron .",
-    "start:dev": "electron . --no-sandbox --disable-gpu",
-    "start:linux": "electron . --no-sandbox",
+    "start:steam-deck": "NEBULA_PROFILE=steam-deck electron .",
+    "start:big-picture": "NEBULA_PROFILE=big-picture electron .",
     "dist": "electron-builder",
+    "dist:steam-deck": "set NEBULA_PROFILE=steam-deck && electron-builder",
+    "dist:big-picture": "set NEBULA_PROFILE=big-picture && electron-builder",
     "run": "electron ."
   },
   "keywords": [],
   "author": "",
   "license": "ISC",
-  "description": "",
+  "description": "A lightweight, privacy-focused browser with controller-friendly Big Picture Mode for gaming and Steam Deck",
   "dependencies": {
     "dompurify": "^3.1.6",
     "electron-updater": "^6.6.2",
     "highlight.js": "^11.9.0",
-    "marked": "^12.0.2"
+    "marked": "^12.0.2",
+    "steamworks.js": "^0.4.0"
   },
   "devDependencies": {
+    "cross-env": "^10.1.0",
     "electron": "^39.2.7",
     "electron-builder": "^23.0.0",
     "electron-nightly": "^39.0.0-nightly.20250811"
@@ -42,7 +46,13 @@
       "icon": "assets/images/Logos/Nebula-Favicon.ico"
     },
     "linux": {
-      "icon": "assets/images/Logos/Nebula-Favicon.png"
+      "target": [
+        "AppImage",
+        "tar.gz"
+      ],
+      "icon": "assets/images/Logos/Nebula-Favicon.png",
+      "category": "Utility",
+      "maintainer": "NebulaBrowser Contributors"
     }
   }
 }