Refactor: Introduce FullScreenContainedLoader and use rememberUpdatedState

This commit introduces `FullScreenContainedLoader` and replaces usages of `FullScreenLoader` where appropriate.

It also updates several composables to use `rememberUpdatedState` for lambda parameters to ensure the latest versions are used.

Additionally, the following changes are included:
- Add a setting to show/hide the attachment button in the chat input bar.
- Implement navigation to `PhotoViewScreen` when a photo attachment is clicked in a message.
- Add "Copy link" and "Copy image" actions to `PhotoViewScreen`.
- Remove unused settings and their corresponding logic from `SettingsViewModel` and `UserSettings`.

app/src/main/kotlin/dev/meloda/fast/presentation/RootScreen.kt

@@ -144,7 +144,8 @@ fun RootScreen(
                 messagesHistoryScreen(
                     onError = viewModel::onError,
                     onBack = navController::navigateUp,
-                    onNavigateToChatMaterials = navController::navigateToChatMaterials
+                    onNavigateToChatMaterials = navController::navigateToChatMaterials,
+                    onNavigateToPhotoViewer = navController::navigateToPhotoView
                 )
                 chatMaterialsScreen(
                     onBack = navController::navigateUp,