feat: Integrate Google Gemini AI for bookmark enrichment and improve content classification

- Add Google Gemini AI SDK dependency (generativeai:0.9.0)
- Implement GeminiRepository with API key management in TokenManager
- Create AI enrichment feature with loading states and error handling in AddLinkViewModel
- Add AI magic button with shimmer animation to AddLinkScreen for automatic bookmark analysis
- Extend ContentType enum with MUSIC and NEWS categories
- Enhance content type detection with expande

app/src/main/java/com/shaarit/presentation/nav/NavGraph.kt

@@ -41,6 +41,7 @@ sealed class Screen(val route: String) {
     object Collections : Screen("collections")
     object Dashboard : Screen("dashboard")
     object Settings : Screen("settings")
+    object Help : Screen("help")
 }
 
 @Composable
@@ -123,6 +124,7 @@ fun AppNavGraph(
                 onNavigateToCollections = { navController.navigate(Screen.Collections.route) },
                 onNavigateToSettings = { navController.navigate(Screen.Settings.route) },
                 onNavigateToRandom = { },
+                onNavigateToHelp = { navController.navigate(Screen.Help.route) },
                 initialTagFilter = tag,
                 initialCollectionId = collectionId
             )
@@ -243,5 +245,16 @@ fun AppNavGraph(
                 onNavigateToDashboard = { navController.navigate(Screen.Dashboard.route) }
             )
         }
+
+        composable(
+            route = Screen.Help.route,
+            deepLinks = listOf(
+                navDeepLink { uriPattern = "shaarit://help" }
+            )
+        ) {
+            com.shaarit.presentation.help.HelpScreen(
+                onNavigateBack = { navController.popBackStack() }
+            )
+        }
     }
 }