feat: Add dedicated pinned bookmarks screen with paginated data loading

- Add getPinnedLinksPaged() query to LinkDao for paginated pinned link retrieval
- Implement getPinnedLinksStream() in LinkRepository with PagingConfig for efficient data loading
- Create PinnedScreen navigation route and composable in NavGraph
- Add "Épinglés" (Pinned) drawer navigation item with PushPin icon in FeedScreen
- Wire navigation callbacks from FeedScreen through NavGraph to PinnedScreen

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

@@ -43,6 +43,7 @@ sealed class Screen(val route: String) {
     object Settings : Screen("settings")
     object Help : Screen("help")
     object DeadLinks : Screen("dead_links")
+    object Pinned : Screen("pinned")
 }
 
 @Composable
@@ -128,6 +129,7 @@ fun AppNavGraph(
                 onNavigateToRandom = { },
                 onNavigateToHelp = { navController.navigate(Screen.Help.route) },
                 onNavigateToDeadLinks = { navController.navigate(Screen.DeadLinks.route) },
+                onNavigateToPinned = { navController.navigate(Screen.Pinned.route) },
                 initialTagFilter = tag,
                 initialCollectionId = collectionId
             )
@@ -270,5 +272,16 @@ fun AppNavGraph(
                 }
             )
         }
+
+        composable(
+            route = Screen.Pinned.route
+        ) {
+            com.shaarit.presentation.pinned.PinnedScreen(
+                onNavigateBack = { navController.popBackStack() },
+                onNavigateToEdit = { linkId ->
+                    navController.navigate(Screen.Edit.createRoute(linkId))
+                }
+            )
+        }
     }
 }